Track: Case Reports

Abstract:

Frictional Asymptomatic Darkening of the Extensor Surfaces (FADES) is a rarely reported dermatologic condition with particularly limited documentation in patients with darker skin tones. We present a case of a 59-year-old woman with Fitzpatrick type V skin who developed symmetric, asymptomatic, thin brown plaques on the extensor surfaces of her elbows, knees, and finger joints. Her occupational history revealed prolonged, low-grade mechanical stress from resting her elbows on her desk while typing. A punch biopsy of a representative plaque on her left elbow demonstrated epidermal papillomatosis, hyperkeratosis, and hypergranulosis without significant inflammation or interface changes, supporting a diagnosis of FADES. A biopsy was helpful in this case as the differential diagnosis included lichen simplex chronicus, psoriasis, and connective tissue disease. Although FADES has been previously described for lighter skin types, its appearance on darker skin may be underrecognized due to reduced pigment contrast and misattribution to dermatoses of systemic or inflammatory origin. This case reinforces the diagnostic value of skin biopsy in ambiguous cases and highlights the importance of considering FADES in the differential diagnosis of symmetric hyperpigmented plaques in skin of color. Our findings expand the clinical and histopathologic spectrum of FADES and support the role of chronic mechanical friction as a non-inflammatory cause of pigmentary change. Improved awareness of this benign but underreported condition may prevent unnecessary workup and improve dermatopathologic recognition, particularly in patients with darker skin tones.

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Ari Gelman