Abstract
Mastocytosis is a disorder characterized by the clonal proliferation of mast cells and their accumulation in skin, bone marrow, liver, and spleen. Cutaneous mastocytosis presents in children in over 90% of the cases and any cutaneous manifestation in an adult is the earliest sign of the systemic disease. A 45-year-old patient presented with itchy dark lesions over the body since childhood and Darier's sign was positive. Skin biopsy showed features of mastocytosis and immunohistochemistry was positive for CD34. Since the patient was refractory to treatment with antihistamines and psoralen-ultraviolet A therapy, injections of interferon alpha were given - 3 million IU twice weekly subcutaneously as they have been proven to improve constitutional symptoms. Very few reports of successful treatment of cutaneous mastocytosis using interferon alpha have been published.