Primary Localized Cutaneous Amyloidosis Secondary to Sand Rubbing in a Wrestler.

A 40-year-old male, wrestler since 15 years of age presented with asymptomatic hyperpigmentation over both his both upper extremities for 10 years. There was no history of preceding itching or redness; of using a nylon brush, scrubbers, or sponges during bathing; or of excessive towel rubbing after bathing and applying cosmetics; however, he had been rubbing sand over both arms for 15 years. He had no personal or family history of atopy, diabetes, or thyroid disease. Cutaneous examination revealed the presence of symmetrical sharply defined reticulate brownish hyperpigmentation over both arms and favoring the left (Figure 1). Dermatoscopy revealed multiple uniform small brown fine streaks radiating from the center becoming reticulated (Figure 2). Hematologic and biochemical studies, in particular thyroid studies, were normal. Histopathologic examination revealed an amorphous eosinophilic deposit in the papillary dermis suggestive of macular amyloidosis (MA) (Figure 3). Methyl violet stain revealed amyloid positive areas (Figure 4), and a diagnosis of MA was made. With the cessation of the sand rubbing and the application of tacrolimus ointment (0.1%), the lesions slowly diminished. (SKINmed. 2022;20:141-143).