One red circular rash on arm that flares up at least twice a year in same spot warm and itchy. when not inflamed, there's always a light brown spot.

See Your Doctor: Your rash suggests a condition called Cutaneous Mastocytosis; excess mastocyte cells accumulate usually in skin & release histamine; causing itching, hives, & more. Can occur as single or multiple lesions, involved skin is darker in color. Stroking or other mechanical trauma to skin can cause symptoms to flare-up. Occurs in children & ages 30-49 yrs. See doctor for correct diagnosis & treatment.