Bullous Mastocytosis: A Rare Variant of Diffuse Cutaneous Mastocytosis.

Mastocytosis is a disease of the mast cells caused by an increase in the number of mast cells due to abnormal proliferation. The disease is associated with a mutation in the c-kit gene, which is a key factor in the development of mast cells. Mastocytosis is classified into two main groups, namely, cutaneous and systemic mastocytosis, based on the site of mast cell accumulation. In cutaneous mastocytosis, the cells purely gather in the skin. In contrast, systemic mastocytosis must affect an internal organ, including the bone marrow, lymph nodes, liver, spleen, and/or the gastrointestinal tract with or without skin involvement. Cutaneous mastocytosis has four distinct presentations, including urticaria pigmentosa, cutaneous mastocytoma, diffuse cutaneous mastocytosis, and telangiectasia macularis eruptive perstans listed from most to least common. This case report presents a rare bullous variant of diffuse cutaneous mastocytosis.