A 22 year-old man presented with a history of multiple lesions on his trunk that began in adolescence and continued to increased in number. The lesions were asymptomatic. There was no other relevant personal or family history.
A very large number of small, predominantly blue-grey papules, mainly on the central chest and abdomen.
What is the diagnosis?
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The diagnosis is eruptive vellus hair cysts (EVHC)
EVHC is an uncommon condition, characterised by occlusion and cystic dilatation of vellus hair follicles.
The cause is unknown, and cases can be sporadic or familial.
EVHC is likely to be familial if it arises in early childhood. Sporadic forms may appear at any age, although they show a clear trend towards occurring during the first three decades of life. Boys and girls are equally affected.
EVHC presents as small, red-brown or blue-grey papules, most commonly on the central chest, although other sites can be affected, and occasionally it can be generalised. There may be just a few cysts, or, often, there may have several hundred.
The main differential diagnosis is steatocystoma multiplex, which is characterised by the development of numerous yellow-white sebum-containing dermal cysts on the upper trunk, and other sites rich in sebaceous glands. In some familial cases of EVHC these two conditions can coexist.
Please follow the link for eruptive vellus hair cysts to learn more about this condition.