A Benign Form of Letterer‐Siwe Disease *

SUMMARY An infant developed, at the age of three weeks, a rash consisting of scaling papules, mainly present on the trunk and later spreading to the scalp. Biopsy showed a dermal infiltrate of histiocytes. The child was otherwise in perfect health and showed none of the other usual clinical features of Letterer‐Siwe disease. Full blood count was normal but a skeletal survey showed one lytic lesion in the right parietal bone. The skin was treated with betamethasone valerate ointment but no treatment was given to the skull infiltrate. By the age of 10 months the skin eruption had completely disappeared and the bony lesion showed radiological signs of healing. Together with fifteen other cases described in the literature, this infant shows that Letterer‐Siwe disease can be benign and self‐limiting.