Eruptive vellus hair cyst in Child
The etiology of EVHCs is unknown. It is thought that a developmental anomaly predisposes to follicular occlusion of vellus hairs, leading to subsequent cystic dilatation of the affected follicle. EVHCs generally occur sporadically but may be inherited in an autosomal dominant fashion or associated with a number of other disorders, including steatocystoma multiplex, trichostasis spinulosa, anhidrotic ectodermal dysplasia, pachyonychia congenita, Lowe syndrome and other neurological disorders, and chronic renal failure. An occurrence of forehead lesions has been reported with use of minoxidil 3% applied to the scalp.
EVHCs characteristically present from childhood through adolescence into early adulthood. Some cases have been reported in elderly patients. Familial cases appear to have an earlier age of onset, with some lesions noted in infancy and even at birth. No predilection in any race / ethnicity or sex has been established.
L72.8 – Other follicular cysts of the skin and subcutaneous tissue
254685008 – Eruptive vellus hair cysts
- Comedonal acne
- Milia – Smaller and yellow / white to skin-colored.
- Steatocystoma multiplex – Different distribution with a predilection for the neck, axillae, and arms.
- Keratosis pilaris – Primarily on the posterior upper arms, rarely involves the chest.
- Folliculitis – Pustules.
- Pityrosporum folliculitis
- Perforating folliculitis
- Molluscum contagiosum – More random distribution, pearly, and always umbilicated.
- Syringomas – Typically periocular.
- Epithelial cysts – Consider Gardner syndrome with multiple epithelial cysts.