Popping papules over the feet

Discussion

Piezogenic pedal papules (PPP) have been described as being both painful and painless. They have been classically described in marathon runners and as incidental findings caused by prolonged weight-bearing over the heels. ^[1] These occur due to fat herniations through the fascial planes. Following degeneration of the normal subcutaneous fibrous trabeculae, fused peripheral chambers or poorly compartmentalized chambers of fat are formed that may protrude through the overlying dermis as yellowish globules. Syndromic association with Ehlers-Danlos syndrome, Prader-Willi syndrome and isolated reports of association with rheumatic heart disease have been cited. ^[2],[3] It has been debated whether such findings in children occur as a common entity due to immature dermal-subcutaneous integrity or is early onset PPP. ^[4]

Clinically, these are better appreciated with standing on direct pressure over the medial, posterior or lateral aspect of heels as multiple, discrete, skin-colored to yellowish, soft to firm papules. Ultrasound examination may reveal fat globules protruding through the dermis and discontinuation of hyperechoic signals at the site of protrusion. This may particularly be useful in patients with painful PPP and in athletes with concomitant hyperkeratosis obscuring clinical features. ^[5]

Pain in these papules have been postulated to be secondary to reduction in dermal thickness due to herniating fat or ischemic compromise affecting the fat and associated nerves. Patients with painless lesions may be reassured while those with painful lesions have been found to benefit from local electro-acupuncture therapy, compression therapy and intralesional steroid-anaesthetic combination injections. ^[6],[7]