A chronic user of crack cocaine may develop characteristic changes in the fingers. Stopping the drug abuse may reverse some of the changes.


The condition is more often seen in women.


Triad of features:

(1) perniosis (hands cold and numb, with or without hyperkeratosis over the knuckles)

(2) atrophy of the finger pulp, most often affecting the thumb and/or index finger

(3) parrot-beak clawing of the fingernail (curvature of the nail associated with the atrophy of the finger pulp)


The changes are believed to be due to peripheral vasoconstriction with ischemia.


Other changes in the hands of chronic cocaine users may include:

(1) Raynaud's phenomenon

(2) palpable purpura

(3) hyperkeratotic palms


The parrot-beak clawing of the fingernails is not specific to cocaine abuse. It can be seen after trauma to the fingertip.


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