Pseudosclerodermatous triad of perniosis, pulp atrophy and 'parrot-beaked' clawing of the nails--a newly recognized syndrome of chronic crack cocaine use.

The number of people dependent on crack-cocaine in the UK has increased substantially in recent years. Some crack-cocaine users develop coarsening changes in the appearance of their hands after prolonged use of the drug. These changes have most often been recognized in females and include: (i) Perniosis with cold, numb hands, sometimes with perniotic hyperkeratosis over the knuckles.(ii) Finger pulp atrophy of the distal part of the pulps of some digits, especially the thumbs and index fingers.(iii) Claw-like curvature of the nails. As the distal pulp is lost, it can no longer splint the nail straight and so the nail curves, claw-like, and reminiscent of a parrot's beak as it clings to the new contour. As the pulp atrophy progresses, the nail eventually also becomes smaller.This triad may be due to ischemia consequent upon peripheral vasoconstriction induced by crack-cocaine. Early changes may resolve with abstinence. In the patients described the syndrome does not appear to be to related to intravenous drug usage. It may occur without concomitant use of heroin, whether smoked or via the intravenous route. The syndrome does not occur in all crack-cocaine users. It is hypothesized that those with a vasoreactive circulation (i.e., those with vasomotor instability/perniosis) are more susceptible to this reaction pattern. The syndrome consisting of the triad of perniosis, pulp atrophy and parrot-beaked clawing of the nails should alert the clinician to the possibility of prolonged crack-cocaine misuse.