Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
VOL.11 NO.5 MAY 2006 2007 VOL.12 NO.4 APRIL Answer to Clinical Quiz Answer : 1. The diagnosis is urticaria pigmentosa (UP). It is the most common skin manifestation of mastocytosis in both children and adults. The lesions appear as small, yellow-tan to reddish-brown macules or slightly raised papules or plaques scattered over the body. Mild trauma, including scratching or rubbing of the lesions, usually causes urtication and erythema around the macules; this is known as the Darier's sign. This is the reason why the mother noticed urtication and blistering in some of the severe lesions (shown in the right infra-scapular area at the back) when rubbing dry the baby's body after bath. Patient with mastocytosis may develop gastrointestinal disease presenting with diarrhoea, abdominal pain and malabsorption. Internal organomegaly affecting the liver and spleen is rarely seen. Bone and marrow involvement presenting with bone pain, anaemia, leucopenia, thrombocytopenia and esoinophilia may occur in systemic disease. Fortunately, our baby did not show any symptoms suggestive of systemic involvement. 2. The diagnosis of UP is suspected on clinical grounds and confirmed by histology. Mast cells, which can be shown by special metachormatic stains such as toluidine blue and Giemsa, are found in increased numbers in dermal papillae, particularly near blood vessels. The greatest increase occurs beneath UP macules and papules where, on average, there is a fifteen- to twenty fold increase in mast cells. Hence, rubbing of these lesional macules degranulates the underlying mast cells and produces urtication and blister when the Darier's sign is elicited. Relevant systemic work up, depending on the signs and symptoms of systemic involvement, may include complete blood picture, liver and renal function tests, chest x-ray, bone scan/ skeletal survey, GI radio-imaging and endoscopic studies and bone marrow aspiration. 3. The aim of the treatment is to control mast cell mediator-induced signs and symptoms such as pruritus. H1 receptor antagonists such as hydroxyzine and doxepin are useful in reducing pruritus, flushing and tachycardia. The addition of H2 antagonists such as ranitidine or cimetidine may be beneficial. Disodium cromoglycate inhibits degranulation of mast cells and may have some efficacy in the treatment of mastocytosis. Topical corticosteroids, such a betamethasone diproprionate ointment applied under plastic-film occlusion may be used to treat extensive UP. Other appropriate treatment is used as indicated to control any systemic disease. As a group, patients with indolent mastocytosis and skin involvement alone have the best prognosis. Among children with isolated UP, as in our patient, at least 50 percent of cases resolve spontaneously by adulthood. Dr. Ka-ho Lau MBBS(HK), FRCP(Glasg), FHKCP, FHKAM(Med) Yaumatei Dermatology Clinic, Social Hygiene Service 39