Botulinum toxin in the treatment of sweat-worsened foot problems in patients with epidermolysis bullosa simplex and pachyonychia congenita.

BACKGROUND Painful foot blistering is a common problem in patients with epidermolysis bullosa simplex (EBS) and pachyonychia congenita (PC). Hyperhidrosis, a condition which can be effectively blocked by plantar injections of botulinum toxin (Btx), often exacerbates the blistering. OBJECTIVES A retrospective evaluation of the effects of Btx injections in 14 patients with EBS and PC with foot blisters and painful callosities. METHODS After informed consent, patients with EBS (n = 6) and PC (n = 8), aged 7-66 years, who had received Btx therapy at our centre since 2003, were included. The treatment consisted of multiple plantar injections of Btx A or Btx B after prior regional or general anaesthesia. Patients were interviewed about the treatment effect and were asked to score the improvement from 0 to 5, where 5 is 'excellent'. One patient with PC with painful callosities was studied by magnetic resonance (MR) spectroscopic microimaging before and after Btx injections to disclose any underlying blisters. RESULTS In total, 76 treatments were evaluated (one to 19 sessions per patient). Thirteen patients (93%) reported reduced plantar blistering and pain; the improvement score was ≥ 4 in four of six patients with EBS and six of eight patients with PC. The mean effect duration was 3 months. No adverse events, apart from mild anticholinergic side-effects in two patients, were noted. MR spectroscopic microimaging showed disappearance of intraepidermal blistering after Btx therapy. CONCLUSIONS Plantar injection of Btx is an efficient, long-lasting and safe treatment of painful blistering and callosities in EBS and PC that can be given repeatedly without loss of efficacy.