Eruptive vellus hair cysts (occlusion and cystic
dilatation of vellus hair follicles) commonly
present as asymptomatic small red, yellow, bluish-grey or brown, papules (occasionally
scaly) on the chest, abdomen (A), and axillae (B) in the second decade of life. They were first reported in 1977. The diagnosis is often made clinically,
because of typical age of onset (before puberty), the site of the lesions, and their appearance. Histopathologic examination reveals a cystic
structure located in the middle or upper dermis. It is lined by a stratified
squamous epithelium with focal features of outer root sheath differentiation at
the level of the follicular isthmus and trichilemmal cornification. The lumen
contains keratin and numerous transversely and obliquely sectioned vellus hair
shafts. Some cysts may show a connecting
pore at the skin surface, the likely mechanism of the spontaneous regression. Also, incision or
puncture of the cyst and examination of the contents in potassium
hydroxide, under a microscope will reveal the vellus
hairs. Eruptive vellus hair cysts can
overlap clinically and pathologically with steatocystoma multiplex (hybrid cysts). The so-called steatocystoma multiplex suppurativa mimics acne conglobata. Twenty-five percent of eruptive vellus
hair cysts cases spontaneously regress through transepidermal elimination. Various methods have been used to treat the lesions but
beware of scarring. The lesions may clear after application of topical
retinoids. Erbium: YAG laser has been successful in treating the lesions*.
![]() |
A |
![]() |
B |
*Kageyama N, Tope WD. Treatment of multiple eruptive hair cysts with erbium : YAG laser. Dermatol Surg 1999; 25: 819–22.
This page was last updated in April 2014.