Black heel (calcaneal petechiae) is a self-limited, asymptomatic, trauma-induced darkening of the posterior or posterolateral aspect of the heel that occurs primarily in young adult athletes.  Black heel was first described in a group of basketball players in 1961. 
Although clinically insignificant, black heel is important because of its close clinical resemblance to melanoma.
A similar lesion termed black palm (tache noir) has been described on the thenar eminence in weightlifters, gymnasts, golfers, tennis players, mountain climbers, and baseball players.  Superficial cutaneous hemorrhages of other areas of the feet have been published in the literature. [4, 5]
Black heel (calcaneal petechiae) is caused by a repeated lateral shearing force of the epidermis sliding over the rete pegs of the papillary dermis. This damages the delicate papillary dermal capillaries, resulting in intraepidermal hemorrhage.
The exact incidence of black heel (calcaneal petechiae) is unknown. One study involving 596 19-year-old sports participants revealed an incidence of 2.9%.  This sports-related dermatosis probably is much more common than has been reported.
Black heel (calcaneal petechiae) primarily occurs in young adult athletes, but it may appear in persons of any age if the appropriate conditions occur.
Prognosis for black heel (calcaneal petechiae) is excellent. Complete clearing is achieved with cessation of the causative activity usually within 2-3 weeks of rest. The lesion of black heel (calcaneal petechiae) usually is asymptomatic, although both pain and tenderness can occur. The black areas always resolve spontaneously if the traumatic inciting events are discontinued.