Hyperpigmented macules in the interscapular region

The patient is a 38-year-old Hispanic woman who presents with a 1-year history of having a very pruritic rash throughout her interscapular area. On examination, she has a circular area of slightly hyperpigmented macules in the interscapular region. The patient complains of pruritus, but she has no pain in the area of the rash. She has no other medical problems and has no systemic symptoms. In addition, the patient has no relevant social or family history and does not take any medications.

Macular amyloidosis

Macular amyloidosis is a chronic pigmentary disorder of the skin; it is found with the highest prevalence in Asia, the Middle East, and South America.1-4 Along with lichen amyloidosis and nodular amyloidosis, it comprises one of three major subtypes of primary localized cutaneous amyloidosis, a condition in which amyloid deposition occurs in otherwise normal skin without associated amyloid deposits in systemic organs.4 Macular amyloidosis mos commonly presents between the ages of 21 and 50 years in patients with Fitzpatrick skin phenotype III or IV.2-4 It is predominantly seen in women, with an estimated femaleto- male ratio approximating 5:1.1-3

Macular amyloidosis is characterized by a rippled pattern of hyperpigmented brown macules characteristically found in the interscapular area of the back.1-5 It is also commonly found on the extensor surfaces of the extremities, and less commonly on the face, breasts, axilla, and buttocks.1-4 Pruritus is the most common symptom that is associated with macular amyloidosis, though some cases are asymptomatic.2,4

The exact cause of macular...