Fox-Fordyce disease.

Fox-Fordyce disease (FFD) is a rare inflammatory disorder that affects the apocrine sweat glands. Clinically, lesions are equidistant, smooth, uniform, firm, folliculocentric papules, which can range in color from flesh-colored to red-brown to slightly yellow. Whereas the axillae are most commonly involved, FFD also can involve the anogenital and periareolar areas, lips, umbilicus, sternum, perineum, and upper medial aspects of the thighs. The underlying etiology of FFD remains unclear although epidemiologic data support a hormonal component because women are more commonly affected than men. Moreover, symptoms initially present after the onset of puberty, flare perimenstrually, and often resolve during pregnancy and after menopause. Histopathologic findings include the obstruction of the apocrine duct by a hyperkeratotic plug in the follicular infundibulum, which is believed to represent the primary pathophysiologic process; subsequent ductal rupture and resulting inflammatory response produce the typical clinical picture. Treatment of FFD is difficult because no one agent has proven particularly effective. Topical and interlesional glucocorticoids are often considered the first-line pharmacologic agents, although use is often limited by concerns for atrophy. Other agents that have shown some success include topical and systemic retinoids, topical clindamycin, topical pimecrolimus cream, benzoyl peroxide, and oral contraceptives. For medication-refractory cases, mechanical destruction or removal of the apocrine glands has been efficacious in small case series.