¹Travis Jackson, BS, University of Missouri School of Medicine, Columbia, MO, USA

²Aspynn Owsley BS, Idaho College of Osteopathic Medicine, Meridian, ID, USA

³Donna Pham, MS, University of California, Riverside, Riverside, CA, USA

⁴Lynn Fadel, BS, California Health Sciences University College of Osteopathic Medicine, USA

⁵Sabrina C. Camacho, BS, Texas Tech University Health Sciences Center School of Medicine, Lubbock, TX, USA

⁶Mary Virginia Glennon, BS, Medical College of Georgia, Augusta, GA, USA

⁷Ashley Bartlett, BS, University of New England College of Osteopathic Medicine, Biddeford, ME, USA

⁸Kelly Frasier, DO, MS - Northwell, New Hyde Park, NY, USA

*Corresponding author: Kelly Frasier, DO, MS, Department of Dermatology, Northwell Health, New Hyde Park, NY, United States, Phone: 3105956882, Email: [email protected]

Received : July 14, 2025 Published : March 04, 2026

ABSTRACT

Nail discoloration in pediatric populations encompasses a wide range of clinical presentations that serve as visible markers of localized trauma, nutritional deficiencies, infectious processes, inflammatory dermatoses, genetic syndromes, and systemic disease. Color changes may appear as isolated findings or in conjunction with systemic signs, providing valuable insight into underlying pathology. In younger children, white discoloration is frequently benign and related to microtrauma or nutritional deficiencies. Longitudinal melanonychia may reflect ethnic pigmentation or, in rare cases, nail matrix neoplasia. Bacterial infections, including Pseudomonas aeruginosa colonization, are implicated in green or brown nail changes in children with frequent aquatic exposure. Fungal infections are also common causes of nail discoloration, often presenting with yellow-brown discoloration. Inflammatory conditions such as psoriasis, along with systemic conditions such as Kawasaki disease, chronic renal or hepatic disease, and gastrointestinal malabsorption syndromes, may manifest as nail plate changes long before overt symptoms appear. Genetic and syndromic conditions, including ectodermal dysplasia, Darier disease, yellow nail syndrome, and nail-patella syndrome often initially present with nail changes, demonstrating how careful nail examination can facilitate early recognition of these disorders. Misinterpretation or dismissal of nail changes may delay early identification of underlying disease. A careful review of nail color, texture, distribution, and progression, combined with a thorough history- including systemic symptoms, physical exposures, and family history- can help narrow the differential diagnosis and improve diagnostic precision. Integrating nail assessment into routine examinations emphasizes its value as a non-invasive, high-yield clinical tool in uncovering both isolated and systemic disease processes in children. 

Keywords: Nail Discoloration, Pediatric Dermatology, Nutritional Deficiency, Systemic Disease, Infectious Nail Disorders, Genetic Syndromes

Citation: Jackson T, et al. (2026). Clinical Patterns, Diagnostic Considerations, and Underlying Etiologies of Nail Discoloration in Pediatric Patients. Dermis. 6(1):59.

Copyright: Jackson T, et al. © (2026).

ABSTRACT

Nail discoloration in pediatric populations encompasses a wide range of clinical presentations that serve as visible markers of localized trauma, nutritional deficiencies, infectious processes, inflammatory dermatoses, genetic syndromes, and systemic disease. Color changes may appear as isolated findings or in conjunction with systemic signs, providing valuable insight into underlying pathology. In younger children, white discoloration is frequently benign and related to microtrauma or nutritional deficiencies. Longitudinal melanonychia may reflect ethnic pigmentation or, in rare cases, nail matrix neoplasia. Bacterial infections, including Pseudomonas aeruginosa colonization, are implicated in green or brown nail changes in children with frequent aquatic exposure. Fungal infections are also common causes of nail discoloration, often presenting with yellow-brown discoloration. Inflammatory conditions such as psoriasis, along with systemic conditions such as Kawasaki disease, chronic renal or hepatic disease, and gastrointestinal malabsorption syndromes, may manifest as nail plate changes long before overt symptoms appear. Genetic and syndromic conditions, including ectodermal dysplasia, Darier disease, yellow nail syndrome, and nail-patella syndrome often initially present with nail changes, demonstrating how careful nail examination can facilitate early recognition of these disorders. Misinterpretation or dismissal of nail changes may delay early identification of underlying disease. A careful review of nail color, texture, distribution, and progression, combined with a thorough history- including systemic symptoms, physical exposures, and family history- can help narrow the differential diagnosis and improve diagnostic precision. Integrating nail assessment into routine examinations emphasizes its value as a non-invasive, high-yield clinical tool in uncovering both isolated and systemic disease processes in children. 

Keywords: Nail Discoloration, Pediatric Dermatology, Nutritional Deficiency, Systemic Disease, Infectious Nail Disorders, Genetic Syndromes.

INTRODUCTION Nail bed and plate evaluations represent an easily accessible yet often underappreciated component of physical examinations. Often associated with systemic diseases, nail changes can indicate the presence and progression of disease. Although easily accessible during physical exams, nail examinations are frequently overlooked in pediatric assessments, resulting in missed opportunities to detect visible signs of underlying conditions. In studies of pediatric populations presenting to dermatologists, 11% of all patients had either physical nail alterations or discolorations [1]. Although some of the nail findings in this population were incidental findings, many cases provided valuable insight into underlying conditions. Nail discoloration refers to any abnormal deviation in nail plate coloration from its normal pink to light brown appearance. Whether presenting as a primary concern or incidentally observed on a routine physical examination, nail discolorations and their possible etiologies must be carefully considered. To complete a comprehensive evaluation, clinicians need to examine all 20 nails, as many conditions present with alterations on a single digit [2]. In addition to a comprehensive physical examination, a thorough history must be taken regarding daily activities, hobbies, and family history of systemic diseases, as these can initially present with nail plate changes.

Overall, nail discoloration can be associated with a wide range of disorders, including cutaneous malignancies, systemic diseases, inherited conditions, nutritional deficiencies, and infectious etiologies. In some cases, nail changes may precede the onset of other clinical symptoms, offering a critical early window for intervention if properly recognized. By incorporating nail evaluation into routine practice, clinicians can identify systemic or local pathology early in the disease course. The objective of this review is to provide a structured, clinically relevant overview of nail discoloration causes in pediatric patients. It highlights the diagnostic significance, underlying etiologies, and associated systemic conditions that occur with pediatric nail discolorations. Common causes of nail are discussed including, benign, infectious, nutritional, systemic, and genetic etiologies. Additionally, it emphasizes the importance of comprehensive nail examinations in the pediatric population. Due to the easily accessible nature of nails, along with the valuable insights they can provide, nail evaluations need to be prioritized as an integral component of the pediatric physical examination.

METHODS

A comprehensive literature search was conducted using electronic databases such as PubMed and EMBASE. The search strategy included keywords such as “pediatric nail discoloration,” “systemic disease nail findings,” “melanonychia in children,” “leukonychia and trauma,” “bacterial nail infections,” “fungal nail infections,” “onychomycosis,” “nutritional deficiency nail changes,” “genetic syndrome nail findings,” “systemic nail changes,” and “inflammatory nail changes,” either individually or in combination. Filters were applied to limit the search to case reports, case series, cohort studies, systematic reviews, and narrative reviews. Inclusion criteria focused on articles addressing nail discoloration either as isolated findings or in conjunction with systemic signs. Priority was given to studies describing nail discoloration findings in pediatric patients aged 0-18 years, with a focus on nail changes associated with systemic disease, genetic syndromes, nutritional deficiencies, and infectious etiologies. Articles discussing pathophysiological linkages of systemic conditions and nail discolorations were also included. Studies unrelated to nail plate alterations, nail discoloration, or nail changes of systemic conditions, as well as those lacking sufficient methodological data, were excluded from the review. The quality of the articles was assessed based on study design and methodology. Data was systematically collected on key topics such as nail discoloration in localized trauma, nutritional deficiencies, infectious processes, inflammatory dermatoses, genetic syndromes, and systemic disease. Findings were summarized and categorized based on underlying etiology of causative condition. Gaps in current understanding of nail discoloration in pediatric patients were also identified to highlight areas for future research.

RESULTS

Many nail disorders present with identical or overlapping clinical features. This makes it essential to evaluate nail distribution, temporal progression, and underlying skin tone to make an accurate diagnosis. For example, longitudinal melanonychia (LM) can have both benign and malignant origins. Benign causes include subungual hematomas, fungal infections, and exogenous pigment deposition, whereas melanocytic LM is a result of melanocytic activation or hyperplasia [3]. In children with darker skin tones, benign LM is particularly common due to increased melanin production in the nail matrix. This physiological pigmentation can be benign in specific ethnic groups and should not immediately raise concern for malignancy. Recent studies have demonstrated that benign LM appears in approximately 80% of African Americans, 50% of Hispanics, and 30% of Japanese individuals [4]. Although LM can be benign in individuals with darker skin tones, clinicians must be aware of signs of subungual melanoma, which can also present as LM. Nearly two-thirds of patients with subungual melanoma present with LM, particularly those with long-standing, widening bands of pigmentation [5,6]. These studies show the importance of not completely dismissing LM and instead assessing evolving patterns that may indicate malignant transformation. Overall, the temporal progression of nail discoloration provides critical diagnostic insight. Acute changes often suggest infectious or traumatic causes, while chronic changes may reflect systemic, genetic, or malignant conditions. Classifying nail abnormalities by age of onset can be another diagnostic tool to narrow down differential diagnoses, as certain conditions are more common among each pediatric age group. In addition to morphology and temporal progression, a thorough clinical evaluation should include the patient's Fitzpatrick skin type, age, medical history, family history, and any associated symptoms. When considered together, these factors can help stratify risk assessment and inform decision-making. This ensures that both benign and severe conditions are appropriately addressed.

Benign Causes and Nutritional Etiologies

Despite their concerning appearance, many nail discolorations are due to underlying benign etiologies. A common cause of leukonychia in pediatric patients is physical trauma to the nail. The soft nails of a newborn are prone to microtraumas, commonly resulting in punctate leukonychia [7]. These white spots are usually transient and resolve spontaneously, making reassurance and supportive care an important part of management. Repeated tapping of nails on a hard surface, such as in sporting activities like basketball, can also result in leukonychia or whitening of the nail surface [8,9]. Such cases highlight how everyday activities can lead to nail changes that may be worrisome in appearance but are ultimately harmless. In addition to trauma, increased nail length can be an underlying cause of leukonychia. Increased nail length can disproportionately increase the axial pressure of the nail, resulting in transverse leukonychia throughout the nail [10]. This mechanical stress can be further exacerbated by poorly fitting footwear or repetitive nail stubbing in active children. Overall, trauma-induced leukonychia is common in the pediatric population, especially as they age and begin participating in physical activities. Clinicians, when encountering leukonychia, need to ask about recent activities and hobbies, as this can help to distinguish trauma-related leukonychia from more concerning causes.

Dietary deficiencies can also present with a variety of nail discolorations. Zinc deficiency can present with half-and-half nails, also called Lindsay’s nails. These nails show a white or light pink color on the proximal half, while the distal half appears pink or reddish-brown, with the darker portion accounting for 20% to 60% of the total nail length [11]. It is essential to take a thorough dietary history after encountering half-and-half nails, as these characteristic findings can be observed in several conditions. These conditions include chronic kidney disease (CKD):Kawasaki disease (KD):type 2 diabetes, and can also be found idiopathically in healthy individuals [12-14]. As zinc deficiency can present with concurrent cutaneous findings, including acral and perioral dermatitis, it is essential to consider this when narrowing down the differential diagnosis. B12 (cobalamin) deficiency commonly results in blue to black hyperpigmentation of nails, as well as colored linear streaks running down the nail plate [15,16]. These pigmentary changes may be an early indicator of systemic deficiency and often resolve with vitamin repletion. Early recognition of these hyperpigmented nail findings may allow for the early correction of the deficiency before it progresses to neurological or hematological complications commonly associated with B12 deficiency. Vitamin C deficiencies commonly present as splinter hemorrhages and nail fragility [17]. These findings reflect capillary fragility in the nails and are often accompanied by other signs of deficiency, such as bleeding gums and easy bruising. Given the wide range of nail findings associated with nutrient deficiencies, the nail plate serves as a valuable, noninvasive window into a child's overall nutritional and systemic health. Recognizing these subtle yet diagnostically significant clues can facilitate earlier interventions and improve long-term nutrition outcomes in pediatric patients.

Bacterial Infections

Green nail syndrome (GNS):or chloronychia, is a distinct nail disorder resulting from a Pseudomonas aeruginosa infection of the nail plate. Clinically, GNS presents with green discoloration of the nail plate, proximal paronychia, and distal onycholysis [18]. Notably, GNS typically affects one or two digits and infrequently involves multiple nails on a hand. This localized presentation helps differentiate GNS from other nail disorders [19]. In pediatric populations, GNS often occurs in individuals with frequent exposure to water, creating an environment that is susceptible to Pseudomonas aeruginosa colonization. The risk of infection increases with repeated mechanical trauma, which compromises nail barrier and integrity. The characteristic greenish hue observed in GNS is attributed to pigments such as pyocyanin and pyoverdine, which are produced by the Pseudomonas bacteria [20]. Although affected nails may appear greenish-black, they are often asymptomatic or present with mild tenderness. These symptoms may be subtle, contributing to the common misclassification of the condition. Diagnosis is primarily clinical; however, further diagnostic tests can be utilized in atypical cases. Ungual fragments and exudates may be gram-stained and cultured to confirm the diagnosis [21]. GNS is most prevalent in older children or adolescents, particularly those engaged in aquatic activities. Due to its subtle presentation, GNS may be underrecognized in pediatric populations, often being misattributed to mechanical trauma. Therefore, heightened awareness is crucial for early identification and management, as delayed diagnosis can lead to persistent Pseudomonas aeruginosa infection and nail dystrophy.

Fungal Infections

Onychomycosis is a fungal infection involving the nail bed and nail plate. While it is less common in the pediatric population than in adults, it remains a significant cause of nail discoloration and dystrophy in children. Dermatophytes, such as Trichophyton rubrum and Trichophyton mentagrophytes, are among the most common causative organisms of onychomycosis as they are responsible for approximately 90% of toenail and 50% of fingernail fungal infections [22,23]. Dermatophytes thrive in warm, moist, and unsanitary environments, including communal bathing areas and contaminated flooring. These environments often lead to asymptomatic tinea pedis infections that can precede fungal nail involvement [24]. Repeated exposure to moisture and microtrauma can disrupt the nail's protective barrier, enabling fungal invasion of the nail bed. Clinically, dermatophyte onychomycosis presents with nail thickening, onycholysis, subungual hyperkeratosis, and discoloration ranging from yellow to brown. Traditional diagnostic methods include potassium hydroxide (KOH) wet mount preparation of subungual debris, and nail clip biopsy with periodic acid-Schiff (PAS) staining [25]. Although dermatophytes are the most common organisms to cause onychomycosis, they are not the only organisms to cause the nail condition. 

Candida species, particularly Candida albicans, can also cause onychomycosis in children. Predisposing factors include chronic paronychia, immunosuppression, and prolonged exposure to moisture [26]. Children with chronic mucocutaneous candidiasis may also be at increased risk of developing candidal onychomycosis due to repeated exposure between the hands and mouth. Clinically, candidal onychomycosis presents with white or yellow discoloration, periungual inflammation, and paronychia, affecting fingernails more commonly than toenails [27,28]. In addition to dermatophytes and candidal onychomycosis, saprophytic molds are also capable of causing nail infections. These molds include Fusarium, Aspergillus, Acremonium, Scytalidium, and Scopulariopsis brevicaulis, and account for nearly 10% of all nail infections [29,30]. Saprophytic molds can colonize the nail surface and penetrate the nail bed following mechanical trauma, often presenting as yellow, brown, or black discoloration of the nail plate. These molds are primarily opportunistic organisms, with infections more common in settings of nail damage, immunocompromisation, or compromised nail integrity [31]. Non-dermatophyte onychomycosis caused by these molds is diagnosed using the same clinical and laboratory methods as other fungal nail infections, including KOH preparation, fungal culture, and PAS staining of nail clippings. As these fungal onychomycosis infections can present subtly clinically, it is important to recognize these findings to avoid delayed diagnosis and treatment.

Systemic Disease Associations

A close physical examination of nails in the pediatric population can serve as a diagnostic clue in the diagnosis of systemic inflammatory disorders. Various nail abnormalities have been associated with KD, including Beau's lines (transverse grooves across the nail plate): leukonychia, and orange-brown chromonychia, with orange-brown chromonychia reported as the most common manifestation [32]. While a definitive association between KD and nail changes has not been well established, numerous case reports have proposed a potential link. Evidence from a study involving 64 patients suggested that peripheral microcirculatory disturbances driven by systemic inflammation in KD may contribute to the development of nail abnormalities early in the disease course [33]. Beyond KD, nail and nailfold findings have also been reported in other pediatric systemic inflammatory conditions, including psoriasis and atopic dermatitis (AD). Among inflammatory nail disorders, psoriasis is a common cause in children, with nail involvement observed in an estimated 17-39% of cases in the pediatric population [34]. Common manifestations differ depending on if patients have nail matrix psoriasis and nail bed psoriasis. Nail matrix psoriasis in children may manifest as nail pitting, leukonychia, or chromonychia; whereas nail bed psoriasis presents with oil drop spots (salmon patches) and onycholysis [34]. The extent of nail involvement in pediatric psoriasis has the potential to serve as an early indicator of extensive cutaneous disease. This makes nail evaluations of pediatric patients with psoriasis, an essential component of any physical exam. Children with AD have also been shown to exhibit nail abnormalities. These include but are not limited to nail pitting, onycholysis, and chromonychia; along with nail fold capillary changes, including reduced capillary density and increased tortuosity [35]. In the context of AD, these vascular changes and subsequent nail findings may reflect broader systemic inflammation that extends beyond the skin surface. Overall, these nail changes may serve as noninvasive clinical clues in the early detection of inflammatory diseases. Increasing awareness of these associations, particularly among dermatologists, may enable clinicians to facilitate better, earlier diagnosis and more effective management of systemic conditions in children.

Renal and Hepatic Correlations

Nail discoloration can often serve as an early and subtle indicator of systemic conditions such as renal and hepatic dysfunction. Several studies have documented specific nail changes associated with these organ systems, highlighting their potential diagnostic value. Characterized by a proximal white portion and a distal brownish-red band, Lindsay's nails are commonly observed in patients with CKD, especially those undergoing hemodialysis. A recent study reported that 20-50% of patients with end-stage renal failure on hemodialysis exhibited this nail change [36]. These findings suggest that Lindsay's nails serve as a visible indicator of systemic disease and can be correlated with declining renal function. In addition to discoloration patterns, structural alterations in the nail can also be present in cases of impaired renal function. Case-control studies have also found that the absence of the lunula (the white crescent at the nail base) is noted in up to 62.9% of CKD patients [37]. This finding can precede other clinical signs of uremia, suggesting its utility as an early marker of advanced renal impairment. Patients with CKD may also exhibit physical nail abnormalities, including splinter hemorrhages, onycholysis, brittle nails, and leukonychia. These changes are thought to result from CKD-related uremia and other associated metabolic disturbances [38]. While these nail findings are commonly associated with renal dysfunction, distinct nail changes have also been observed in hepatic conditions, offering additional diagnostic insight into liver-related systemic disease. Terry's Nails, leukonychia, and nail dystrophy are important clinical findings in pediatric patients for hepatic disorders. Described as nails that are white with a red-brownish band at the distal tip of the nail, Terry's nails are frequently associated with underlying hepatic dysfunction [39]. They are thought to be due to underlying alterations in the vascularization of the nail bed. In disorders with impaired liver function, the resultant hypoalbuminemia may contribute to this nail change by causing vascular and tissue damage to the nail bed. Overall, these findings regarding renal and hepatic dysfunction reinforce the clinical value of nail findings as noninvasive markers for assessing systemic health in pediatric populations.

Gastrointestinal Malabsorption Syndromes

Nail findings in children can serve as subtle indicators of underlying gastrointestinal (GI) malabsorption syndromes. While direct studies focusing solely on nail changes in pediatric malabsorption are limited, several conditions associated with malabsorption exhibit characteristic nail and skin manifestations. Koilonychia, characterized by thin, concave nails and increased nail fragility, is often linked to iron deficiency anemia [40]. In children, iron deficiency can result from malabsorption syndromes such as celiac disease or chronic GI bleeding. The finding of koilonychia, or "spoon nails," needs to be differentiated from trauma, as a traumatic mechanical insult to the nails may also cause nail concavity [41]. This nail change may be an early sign prompting further evaluation for underlying malabsorptive conditions. Cyanotic changes to the nail along with digital clubbing, characterized by a bulbous enlargement of the fingertips with distortion of the nail bed angle, has been observed in pediatric patients with chronic malabsorption syndromes, such as cystic fibrosis and celiac disease [42]. Its presence, particularly when bilateral and progressive, may suggest long-standing intestinal or pulmonary inflammation, ultimately leading to chronic hypoxia, which can result in nail changes. Acrodermatitis enteropathica, a rare genetic disorder that affects zinc absorption, leads to systemic zinc deficiency. Some nail abnormalities associated with this disorder include paronychia, onychodystrophy, and Lindsay's nails, as previously mentioned [43]. These nail changes often occur concurrently with other manifestations of zinc deficiency. These manifestations include alopecia, diarrhea, and overall growth delay [44]. These nail manifestations of malabsorption syndromes highlight the importance of considering nutritional deficiencies in the differential diagnosis of nail changes. The nail findings associated with malabsorption syndromes and nutritional deficiencies warrant a comprehensive evaluation for potential underlying GI disorders. Early recognition and intervention are crucial in preventing long-term complications.

Genetic and Syndromic Conditions

Ectodermal dysplasias comprise a large group of inherited disorders that affect two or more ectodermal structures, commonly involving the nails, hair, teeth, and sweat glands [45]. Nail findings may include thickened, slow-growing nails, leukonychia, and, in some cases, complete nail dystrophy or nail absence (anonychia): reflecting the severity of ectodermal disruption [46]. This rare disorder is typically inherited in an X-linked recessive pattern and can significantly impact patients' quality of life. The EDA, EDAR, and EDARADD genes encode ectodysplasin A, a protein critical for embryonic development through its role in signaling pathways that mediate interaction between the ectoderm and mesoderm [45]. Mutations in these genes disrupt ectodysplasin A production and, therefore, lead to disrupted structures derived from the ectoderm and mesoderm. This ultimately leads to abnormal development of nails, hair, sweat glands, and teeth, the hallmark features of ectodermal dysplasia. Identifying common nail findings can aid in the diagnosis of this group of X-linked diseases, especially if a family history of associated symptoms is present. Noticing early nail changes associated with the condition may allow for prompt genetic diagnosis, which also enables timely supportive care and counseling, improving patient outcomes.

Darier disease (DD), also known as keratosis follicularis or dyskeratosis follicularis, is an inherited disorder characterized by distinctive nail findings. Patients often present with V-shaped nicking at the free margin of the nails, subungual hyperkeratosis, and longitudinal red and white streaks [47]. These nail findings reflect the underlying defects in keratinocyte adhesion, which is critical to the pathophysiology of the disease course. The condition arises from mutations in the ATP2A2 gene, located on chromosome 12q23-24.1, which encodes the SERCA2 protein —a calcium pump critical for intracellular calcium regulation [47]. The SERCA2b isoform, predominantly expressed in the epidermis, is essential for proper cell adhesion and epidermal integrity. Dysfunctional SERCA2b disrupts calcium signaling and interferes with the formation and maintenance of cell adhesion complexes, leading to the clinical manifestations of DD [47]. Nail findings are often one of the earliest clues to diagnosis and can precede cutaneous lesions, particularly in mild or atypical cases. Recognizing these characteristic nail features is crucial for dermatologists, particularly when skin lesions are subtle or absent, as they can prompt timely evaluation and diagnosis.

Yellow nail syndrome (YNS) can be characterized by slow-growing, hard, yellow, dystrophic nails. It is associated with a triad of pulmonary disease, lymphedema, and nail changes, characterized by the absence of a cuticle or lunula [48]. Recognizing this disorder based on its characteristic nail findings can help clinicians anticipate associated clinical features and deliver more personalized, proactive care tailored to the expected disease course.​​ The pathogenesis of YNS is not fully understood, but it is believed to involve dysfunction in the lymphatic system. This dysfunction may lead to impaired lymphatic drainage and changes in capillary permeability, which can contribute to characteristic symptoms such as lymphedema and nail discoloration [48]. These physiologic changes may also explain the slowed nail growth and thickened consistency often seen in YNS, as the altered fluid dynamics can affect nail matrix function. The syndrome is often acquired and most commonly affects adults over the age of 50; however, there are reports of its occurrence in children and newborns [49]. Despite some cases resolving spontaneously, many symptoms recur and require ongoing symptomatic management. It is essential to rule out other causes of xanthonychia when evaluating for YNS. If detected early enough in the syndromic course, it may help prevent further complications of the condition (Table 1).

Table 1. Nail Color and Morphologic Changes with Associated Conditions and Diagnostic Clues.

Nail color/type	Associated conditions	Diagnostic Clues
White (leukonychia)	Trauma, zinc deficiency, Kawasaki disease (KD):nail matrix psoriasis, ectodermal dysplasia	- Trauma: punctate spots or longitudinal leukonychia
		- Zinc deficiency: half-and-half nails (proximal white/light pink, distal pink/reddish brown)
		- KD: transverse leukonychia (Beau’s lines)
		- Nail matrix psoriasis: leukonychia patterns
		- Ectodermal dysplasia: thickened, slow-growing, or dystrophic nails
Black/brown (melanonychia)	Ethnic pigmentation, subungual melanoma, B12 deficiency, junctional nevi	- Ethnic pigmentation: longitudinal pigmented bands, usually multiple nails
		- Subungual melanoma: solitary, widening, irregular pigmented bands
		- B12 deficiency: dark pigmented streaks
		- Junctional nevi: benign longitudinal bands
Blue/black	Vitamin B12 deficiency	- Blue nails or linear streaks indicating early systemic deficiency
Yellow	Onychomycosis (fungal):Yellow Nail Syndrome (YNS):psoriasis	- Onychomycosis: yellow-brown discoloration, nail thickening, onycholysis
		- YNS: thick, slow-growing yellow nails with absent lunula and possible lymphedema/pulmonary disease
		- Psoriasis: yellow chromonychia and nail pitting
Green	Pseudomonas aeruginosa (Green Nail Syndrome)	- Green-black discoloration of nail plate
		- Common in swimmers or nails exposed to frequent moisture or trauma
Orange/brown	KD, psoriasis	- KD: orange-brown chromonychia
		- Psoriasis: oil-drop spots (salmon patches)
Beau’s lines	KD, systemic illness	- Transverse nail grooves with white discoloration caused by systemic stress or febrile illness
Brittle/onchodystrophy	Zinc deficiency, ectodermal dysplasia, fungal infection	- Zinc deficiency: ridging, thinning nails
		- Ectodermal dysplasia: abnormal dystrophic nail shape
		- Fungal infection: nail fragility and thickened nail plate
Koilonychia (spoon nails)	Iron deficiency, Celiac disease, GI malabsorption	- Thin, concave nails often associated with anemia or malabsorption syndromes
Blue hue/clubbing	Chronic hypoxia, Cystic fibrosis, Celiac disease	- Bulbous fingertips and bluish nails
		- Indicative of chronic pulmonary or GI disease
Absent lunula	Chronic kidney disease (CKD)	- Missing lunula in over half of patients with advanced renal failure
Terry’s nails	Hepatic dysfunction, hypoalbuminemia	- White nails with a distal red-brown band; related to vascular changes in liver disease
V-shaped nicking	Darier Disease	-Notching at free edge of nails
		-Often accompanied by longitudinal red and white streaking

 

DISCUSSION

Nail discoloration in pediatric patients often signals more than superficial change, functioning instead as an early marker of systemic, infectious, or genetic disease. While common clinical features may be perceived as benign, dismissing them without context can lead to a delayed essential diagnosis. For instance, melanonychia affecting a single digit may reflect early melanocytic proliferation rather than routine ethnic pigmentation and, therefore, warrants careful monitoring [50]. This form of melanonychia has also been associated with junctional nevi and, in rare cases, early nail matrix tumors. The diagnostic significance of nail findings is further exemplified in systemic illnesses, such as KD, where nail changes, like onychomadesis and orange-brown chromonychia, can occur before classic mucocutaneous symptoms [34]. These examples highlight the broader implications of nail discoloration and affirm the importance of integrating nail assessment into clinical decision-making.

A structured clinical approach is paramount in nail evaluation, as it significantly enhances diagnostic clarity and minimizes unnecessary intervention. A comprehensive nail assessment includes an analysis of color, distribution, surface texture, and progression over time. For instance, green discoloration is often indicative of Pseudomonas aeruginosa colonization, especially in children who frequently engage in aquatic activities or have compromised nail barriers. Understanding this association is crucial for informed antimicrobial choice and prevention strategies. Inflammatory nail disorders, such as psoriasis and AD, may manifest with features like pitting, chromonychia, and onycholysis, which can correlate with more severe systemic involvement, including psoriatic arthritis [34]. These nail findings guide clinicians in assessing disease burden and may prompt earlier use of systemic therapy. It is also important to distinguish between benign conditions and those that require urgent evaluation. For example, nail biopsies in children should be reserved for cases with a high suspicion of malignancy due to risks such as permanent scarring [50]. These structured evaluations refine diagnostic pathways while preserving pediatric patients from unnecessary procedures.

Routine integration of nail assessment into pediatric exams is a noninvasive strategy of detecting early clues to diseases that may not yet be clinically apparent. Conditions may present with abnormal nail findings before other systemic signs emerge. For instance, ectodermal dysplasia frequently presents with anonychia and micronychia before its formal diagnosis [51]. Recognizing these features allows for timely genetic referral and multidisciplinary intervention. Nail changes can also reflect treatment response or disease exacerbation in chronic dermatologic conditions. For example, worsening trachyonychia in a child with alopecia areata may signal autoimmune activity that justifies escalation of care [50]. Many nail disorders in children are self-resolving, and overtreatment can lead to avoidable harm. It is valuable for providers to learn to differentiate between conditions that require intervention and those that are appropriate for observation. Ensuring that pediatricians and dermatologists are trained with these skills makes the nail assessment an essential, proactive component of comprehensive care.

CONCLUSION

Nail discoloration and morphological changes in pediatric populations reflect a broad and diverse spectrum of age-specific differential diagnoses, ranging from transient benign findings to systemic and genetic pathology. Careful assessment of nail color, texture, distribution, and temporal progression, along with a thorough history, can offer promising insight into underlying etiologies. Local causes such as microtrauma from physical play and repetitive mechanical stress explain many cases of leukonychia in young children. Chronic exposure to moisture, combined with compromised nail barriers, increases susceptibility to bacterial and fungal pathogens, which can cause the nail plate to discolor green or yellow. Nail changes can also be indicators of a wide variety of systemic diseases. These include, but are not limited to, nutritional deficiencies such as zinc or iron deficiency, GI malabsorption syndromes, renal or hepatic failure, autoimmune conditions, and inflammatory processes, including KD. Certain rare genetic syndromes can present with nail abnormalities in their early stages. These include ectodermal dysplasia, DD, nail-patella syndrome, and YNS. In the cases of these genetic disorders, recognition of nail patterns may offer the earliest visible indication of underlying disease processes. Given the easily accessible nature of nail exams and the high diagnostic yield they can provide, nail examinations must be prioritized and standardized as a crucial component of pediatric physical examinations. The integration of physical examination, comprehensive history-taking, and appropriate diagnostic testing has the potential to improve diagnostic precision and support the earlier identification of complex nail disorders in pediatric patients.

Clinical practice implications of these common nail discoloration patterns highlight the need for routine incorporation of complete nail examinations into well-child exams, particularly for patients with chronic medical conditions, nutritional concerns, or unexplained systemic symptoms. Clinicians should be able to recognize age and skin tone specific variants of normal nail discolorations, along with common pathologic causes. Standardized documentation of nail findings within the electronic health record at annual visits may also support longitudinal tracking of more subtle changes over time. Future directions for research should include the development and validation of pediatric-specific nail assessment tools. Ideally, these tools will incorporate photographic standards, symptom checklists, and risk stratification algorithms based on age and medical history. Prospective cohort studies are needed to evaluate long term outcomes of nail findings as early markers of systemic disease. Additionally, longitudinal studies are needed to assess whether early identification of nail changes leads to improved clinical outcomes or reduced disease burden. Studies evaluating artificial intelligence-assisted image analysis in pediatric nail assessments could also have the potential to advance early detection. Overall, a standardized, evidence based framework for pediatric nail evaluations would increase diagnostic accuracy, increase early identification of nail conditions, and strengthen the role of routine nail assessments as a non-invasive and cost effective tool in pediatric evaluations.

 

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