Hidradenitis suppurativa resulting in systemic amyloid A amyloidosis: a case report and review of the literature.

Hidradenitis suppurativa is a chronic, inflammatory disease of the follicular epithelium that presents as tender, subcutaneous nodules in an intertriginous distribution with sinus tract formation. Most commonly, hidradenitis suppurativa results in local complications, such as scarring and infection. However, systemic complications, such as anemia and arthropathies, have also been described. Herein, we report an unusual case of systemic amyloid A secondary to hidradenitis suppurativa. We describe a 39-year-old man with a long history of recurrent, tender, erythematous nodules in the axillary and anogenital regions, resulting in abscesses, sinus tract formation, and large areas of scarring. After 21 years of cutaneous disease with concurrent elevated systemic inflammatory markers, the patient was noted to have significant proteinuria. A kidney biopsy and immunostaining revealed deposits of amyloid A. Echocardiogram and electrocardiogram showed ventricular and atrial wall thickening with an appearance consistent with cardiac amyloid deposition. Systemic amyloid A amyloidosis is a serious, but rare, complication of chronic inflammatory disorders, including hidradenitis suppurativa, with potential multi-organ involvement including renal and cardiac manifestations. Amyloid A amyloidosis should be suspected in patients with chronic inflammatory cutaneous diseases who present with renal abnormalities, especially proteinuria or the nephrotic syndrome.