Sports-related pads

Knuckle pads, first described by Garrod in 1893,(1) are benign, asymptomatic, well-circumscribed, smooth, firm, skin colored papules, nodules, or plaques. They most commonly occur on the dorsal aspect of the proximal interphalangeal joint of the finger,(2) but also may occur on the dorsal aspects of the foot over joints.(3-5) Knuckle pads may be inherited or acquired.(1) While some authors suggest that trauma is not a significant factor,(6) acquired knuckle pads have been associated with repetitive friction and trauma,(2,7) and may resemble athlete's nodules ( also referred to as collagenomas).(1) Histologically, knuckle pads are characterized by hyperkeratosis, hypergranulosis, proliferation of fibroblasts and capillaries, and thickened and irregular collagen bundles.(1) Few cases of knuckle pads involving the lower extremities have been reported.(7) Knuckle pads of the feet have been described in association with inherited syndromes, such as acrokeratoelastoidosis Costa,(3) a syndrome of knuckle pads, leukonychia and deafness,(4) and a syndrome of knuckle pads, leukonychia, deafness and keratosis palmoplantaris.(5) We report a case that illustrates an unusual presentation of acquired knuckle pads of the feet secondary to repetitive friction from athletic gear.