Table 1.

Classification of nail diseases in pediatric patients from birth to 5 years of age

	Age	Physiological alterations	Pathological alterations
Newborns	Birth	Koilonychia Transient physiological onychoschizia Traumatic punctate leukonychia “Pseudo-hypertrophy” of the hallux	Clubbing Nail-patella syndrome Multiple ingrown fingernails
Infants	1 month to 1 year	Transient light-brown or ochre pigmentation of the proximal nail fold Beau's lines of the fingernails	Ectodermal dysplasias
Toddlers	1–3 years	Punctate leukonychia Pitting	Dyskeratosis congenita Epidermolysis bullosa Congenital malalignment of the hallux Congenital hypertrophy of the lateral nail folds Vertical implantation of the nail of the 5th toe Curved nail of the 4th toe Anonychia and micronychia Beau's lines and onychomadesis
Preschoolers	3–5 years	Chevron or herringbone nails	Pachyonychia congenita Acute paronychia Blistering distal dactylitis Herpes simplex Ungual warts Trachyonychia Nail lichen striatus Longitudinal melanonychia