Paeds · paediatric-dermatology
Nail disorders in children
Also known as Paediatric nail disease · Onychomycosis in children · Trachyonychia · Twenty-nail dystrophy · Ingrown toenail · Paronychia · Longitudinal melanonychia in children
Fellowship topic on nail disorders in children: the nail unit anatomy and the site-based diagnostic principle that matrix lesions change nail shape and surface, nail bed lesions change colour and attachment, and nail fold lesions cause swelling and infection; the classification of paediatric nail disorders into normal and developmental variants, traumatic, infectious (acute and chronic paronychia, onychomycosis), inflammatory and skin-disease associated (psoriasis, alopecia areata, lichen planus, trachyonychia), congenital and genetic (congenital malalignment of the great toenail, nail-patella syndrome, pachyonychia congenita), nail tumours (pyogenic granuloma, subungual exostosis, viral warts, longitudinal melanonychia and the nail matrix naevus) and systemic nail signs (clubbing, koilonychia, Beau lines); the confirm-before-treat principle for onychomycosis with mycology before systemic therapy and weight-based terbinafine or itraconazole; the conservative-first management of the ingrown toenail with wedge excision and phenolisation for recurrent disease; the reassurance and topical steroid approach to idiopathic trachyonychia; the recognition that longitudinal melanonychia in a child is usually benign; the red flags for urgent referral; and the ANZ and international dermatology guidance.
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Target exams
Red flags
- A progressive, widening or darkening longitudinal pigmented band in a single nail of a fair-skinned child — possible nail melanoma; refer urgently to dermatology for dermoscopy and biopsy assessment
- A persistent subungual lesion with nail destruction, elevation or bone involvement — possible subungual exostosis or malignancy; image the distal phalanx and refer
- Progressive nail thinning and dystrophy with a forward-growing scar (pterygium) — scarring nail lichen planus; urgent potent topical or intralesional steroid to the matrix to prevent permanent nail loss
- A rapidly progressive nail fold or digital mass that bleeds easily, or a destructive vascular lesion — possible pyogenic granuloma or tumour; refer for specialist assessment
Life stages
Care settings
Clinical exam formats
Board mappings
- General Paediatrics and Dermatology: anatomy-based approach to the disordered nail; recognition and stepwise management of onychomycosis, paronychia, ingrown toenail and trachyonychia; the red flags for referral
- Musculoskeletal and skin: recognition of nail psoriasis and juvenile psoriatic arthritis screening; clubbing and systemic nail signs
- Renewed curriculum — Dermatology: confirm-before-treat for onychomycosis, weight-based terbinafine dosing, dermoscopic assessment of longitudinal melanonychia, and the congenital and genetic nail disorders
- Population child health: equity of access to paediatric dermatology for rural and remote families with chronic nail disease
- General Paediatrics: diagnosis and conservative-first management of the common paediatric nail disorders and recognition of the red flags for urgent referral
- Psychosocial: the burden of visible nail dystrophy and nail biting in school-age children and adolescents
- Long Case / Structured discussion: a child with onychomycosis, an ingrown toenail or trachyonychia — diagnosis, confirmation, stepwise management, prognosis and the red flags
- Communication station: explaining conservative nail care, the confirm-before-treat principle for suspected onychomycosis and the reassurance around benign paediatric nail variants to a family
- Level 2 / 3 — Dermatology: anatomy-based assessment and stepwise management of common paediatric nail disorders
- Growth and development and health promotion: normal nail variants in infants, nail biting and footwear-related disease in adolescents
- Foundation of Practice (FOP): normal nail variants, the common acquired nail disorders, and the differential of the thickened nail, the transverse groove and the longitudinal pigmented band
- Applied Knowledge in Practice (AKP): confirm-before-treat for onychomycosis, conservative-first management of the ingrown toenail, and the red flags for referral
- History-taking and management: the child with an ingrown toenail, onychomycosis or trachyonychia, including confirmation, stepwise treatment and prognosis
- Communication: explaining conservative nail care and the reassurance around benign variants to a family
- General Pediatrics Content Outline — nail disorders: anatomy-based approach, common acquired disorders, confirmation and stepwise management
- Dermatology: onychomycosis, paronychia, ingrown toenail, trachyonychia and the red flags
- Genetics and orthopaedics: nail-patella syndrome recognition
- Patient Care: anatomy-based diagnosis and cause-matched, conservative-first management of paediatric nail disorders
- Medical Knowledge: nail unit anatomy and growth, the confirm-before-treat principle for onychomycosis, weight-based terbinafine dosing and dermoscopic assessment of melanonychia
- Systems-Based Practice: equity of access to paediatric dermatology and the appropriate threshold for specialist referral
- Medical Expert: paediatric nail disorders diagnosis, confirmation and stepwise management across the congenital, infectious, inflammatory, traumatic and neoplastic spectrum
- Health Advocate and Collaborator: coordinated dermatology and primary care for chronic nail disease and the psychosocial burden of visible dystrophy
- Communicator: explaining conservative nail care and the reassurance around benign variants to children and families
Two ways a child's nail changes colour and lifts
Onychomycosis (fungal)
Nail bed psoriasis
The nail unit is a production line, and each station has its own signature fault. The matrix is the factory floor — damage it and the shape and surface come out wrong (pitting, Beau lines, trachyonychia, ridges). The nail bed is conveyor plate rides on — inflame it and the colour and attachment change (onycholysis, oil-drop sign, subungual haematoma). The nail fold is the frame around the nail — infect it and you get swelling and pus (paronychia). Remember that the nail grows about 3 mm a month and takes 6 months (fingernail) to 12 to 18 months (toenail) to replace itself, which is why a single illness leaves a Beau line that crawls distally over months. [1] [2]
Overview & Definition
Picture a ten-year-old brought in because one toenail has turned thick and yellow, or a teenager whose great toe is red and weeping where the nail digs in, or a five-year-old whose twenty nails look rough and sandpaper-like. None of these are dangerous, yet each can disrupt a child's comfort, sport and self-image, and each is solved faster once you know where in the nail unit the problem lives. [1] [2]
The nail unit is a small but intricate structure. The nail matrix is the germinative epithelium tucked under the proximal nail fold that generates the nail plate; its distal edge shows through the nail as the pale half-moon called the lunula. The nail plate is the hard keratin structure we call the nail, and it rides forward over the tightly adherent nail bed. The proximal and lateral nail folds frame the nail, and a thin layer of keratin called the cuticle (eponychium) seals the gap between the fold and the plate, protecting the matrix. At the tip, the hyponychium marks where the plate finally separates from the bed. Knowing these parts is not anatomy for its own sake — it is the diagnostic method, because the sign you see points back to the part that is diseased. [1] [2]
The clinician's task has three layers. The first is recognition and localisation — deciding whether a thickened nail, a transverse groove, a pigmented band or a swollen fold is fungal, inflammatory, traumatic, congenital or neoplastic. The second is cause-matched, conservative-first management — confirming onychomycosis before treating it, draining a paronychia, and reassuring the family of a child with benign trachyonychia. The third is vigilance for the few red flags — a changing or destructive nail lesion — that demand urgent specialist referral. Nail disorders in children are common and usually benign, but they reward a methodical, anatomy-led approach. [1] [3]
References12ShowHide
- [1]Bellet JS Pediatric Nail Disorders. Dermatol Clin, 2021.PMID 33745636
- [2]Smith RJ; Rubin AI Pediatric nail disorders: a review. Curr Opin Pediatr, 2020.PMID 32692049
- [3]Axler EN; Bellet JS; Lipner SR Tackling Inflammatory and Infectious Nail Disorders in Children. Cutis, 2024.PMID 39159345
- [4]Solís-Arias MP, García-Romero MT Onychomycosis in children. A review. Int J Dermatol, 2017.PMID 27612431
- [5]Jacobsen AA; Tosti A Trachyonychia and Twenty-Nail Dystrophy: A Comprehensive Review and Discussion of Diagnostic Accuracy. Skin Appendage Disord, 2016.PMID 27843915
- [6]Pourchot D; Bodemer C; Phan A; Bursztejn AC; et al Nail Psoriasis: A Systematic Evaluation in 313 Children with Psoriasis. Pediatr Dermatol, 2017.PMID 27873356
- [7]Ricardo JW; Bellet JS; Jellinek N; Lee D; et al Evaluation and diagnosis of longitudinal melanonychia: A clinical review by a nail expert group. J Am Acad Dermatol, 2025.PMID 40023404
- [8]Ansari MS; Mahmoudi H; Sadeghinia A; Azizzadeh-Roodpishi S; et al Dermoscopic Evaluation of Longitudinal Melanonychia in Children: A Prospective Study. Indian J Dermatol, 2021.PMID 34759421
- [9]Bernal Masferrer L; Matei MC; Gilaberte Calzada Y; Navarro Campoamor L [Translated article] Congenital and Hereditary Nail Disease. Actas Dermosifiliogr, 2024.PMID 38972583
- [10]Khan S; Basit S; Habib R; Kamal A; et al Genetics of human isolated hereditary nail disorders. Br J Dermatol, 2015.PMID 26149975
- [11]Forrest CE; Casey G; Mordaunt DA; Thompson EM; et al Pachyonychia Congenita: A Spectrum of KRT6a Mutations in Australian Patients. Pediatr Dermatol, 2016.PMID 27041546
- [12]Braga Silva J Fingernail injury in children. Hand Surg Rehabil, 2024.PMID 36682538