Acquired brachial cutaneous dyschromatosis (ABCD) is a rare, asymptomatic skin disorder that presents with irregular, brown, hyperpigmented patches interspersed with hypopigmented macules on the dorsal aspect of the forearms.

There are two major hypotheses concerning the etiology of ABCD. The first suggests an association between hypertension (HTN) or antihypertensive agents (specifically angiotensin-converting enzyme inhibitors [ACEIs]). Studies have reported that nearly 65% of patients with ABCD have concurrent HTN, and of those 65%, the vast majority were utilizing ACEIs for treatment. The second proposes cumulative solar damage as the cause. Around 45% of patients diagnosed with ABCD have simultaneous poikiloderma of Civatte, lending support to the chronic sun damage hypothesis.

From the existing case reports, middle-to-older-aged adults with Fitzpatrick phototypes III and IV are most affected. Women vastly outnumber men, with postmenopausal women especially affected.