Diffuse cutaneous mastocytosis (DCM) is a rare form of cutaneous mastocytosis (CM; see this term) characterized by generalized erythroderma, various degrees of blistering, skin with a ''peau d'orange'' appearance and the accumulation of mast cells in the skin. At least two DCM variants are recognized, one with extreme blistering (Bullous DCM; see this term) and one with infiltrations (Pseudoxanthomatous DCM; see this term).