Treatment of pachyonychia congenita with plantar injections of botulinum toxin.

Pachyonychia congenita (PC) is a rare genodermatosis which may be associated with painful, focal hyperkeratosis on the soles. Plantar sweating at high ambient temperatures increases the blistering of the callosities. We report three patients with PC who had great problems in walking, especially during summer time. They were treated with intracutaneous plantar injections of botulinum toxin type A (Dysport, 100 U mL(-1); Ipsen, Slough, U.K.) after prior intravenous regional anaesthesia of the foot with a low tourniquet and 25 mL prilocaine (5 mg mL(-1)). Within a week all three patients experienced dryness and a remarkable relief of pain from plantar pressure sites. The effect duration was 6 weeks to 6 months. Repeated injections over a 2-year period confirmed the good results, with no side-effects or tachyphylaxis noted.