A treatment protocol for botulinum toxin injections in the treatment of pachyonychia congenita‐associated keratoderma

Abstract

Severely debilitating plantar keratoderma pain is the most distressing clinical feature of pachyonychia congenita (PC). Several earlier publications have reported therapeutic success with plantar injections of botulinum toxin (Btx). To describe our 4-year experience during which we administered a total of 30 plantar Btx injections to five patients with PC following an optimized protocol. Five patients with PC (age 21-54 years) who were treated at our medical centre from April 2015 to June 2018 were included in the study. After an ultrasound-guided nerve block performed by an anaesthesiologist, the patients received plantar intradermal injections of Btx A. To ascertain the effect of the treatment, we used a dedicated quality-of-life questionnaire for patients with PC (PCQoL) and asked the patients to evaluate the intensity of eight parameters pertaining to their symptoms at baseline and before every treatment session. At study closure, patients were asked to evaluate the maximal improvement in the same eight parameters throughout the study period. All patients demonstrated a decrease in PCQoL scores during the follow-up period. All patients showed a significant improvement in PCQoL after the first treatment session and at the last evaluation (P = 0·043). The scores with the best improvement concerned morning feet burning and long-distance walking (> 500 m). The scores were significantly lower if the intervals between Btx injections were <100 days. Btx treatment of PC-associated keratoderma following an optimized protocol leads to a major change in patients' quality of life. What's already known about this topic? Plantar pain is considered by patients to be the most severe and debilitating manifestation of pachyonychia congenita (PC). Over the past few years, a number of reports have shown that plantar injections of botulinum toxin (Btx) reduce or even eliminate pain, blistering and callosities in patients with PC. However, the injection technique, doses of Btx and methods of anaesthesia varied between reports and patients. What does this study add? Here we report our 4-year experience in providing 30 treatments to five patients following an optimized protocol. Btx was found to provide a quantifiable improvement in all patients treated. What is the translational message? Btx treatment of PC-associated keratoderma using a structured approach, which includes the use of a sufficient dose of Btx (200-400 U of onabotulinumtoxinA or 500-1000 U of abobotulinumtoxinA), and regular intervals between treatment sessions (of < 100 days), leads to a major change in patients' quality of life.