Botulinum toxin type‐A for the treatment of inverse psoriasis

Abstract Objective To evaluate the efficacy of botulinum toxin type‐A (BoNTA) for the treatment of inverse psoriasis. Background The use of BoNTA in inverse psoriasis would be a novel approach compared with conventional treatments and may act at the neuroglandular junction level to reduce local sweating with its consequent skin maceration and secondary infection and at the extra‐junction level to inhibit the liberation of neuropeptides and other pro‐algogenic substances responsible for inflammation, hyperkeratosis and pain transmission. Patients Fifteen patients with a confirmed diagnosis of inverse psoriasis were enrolled into the study. The psoriasis was located in several areas: armpits (7 patients), submammary sulcus (6 patients), intergluteal folds (7 patients), inguinal folds (5 patients) and umbilicus (1 patient). Methods BoNTA treatment comprised individual injections 2.8 cm apart of 2.4 U BoNTA, with a total dosage between 50 and 100 U per patient depending on the extent and severity of the psoriasis. Patient assessments were done pre‐treatment and at 2, 4 and 12 weeks post‐treatment. The erythematous area was defined using objective photographic evidence, and subjective patient assessment of pain and itch was assessed using a 10‐point visual analogue scale scale. Results Subjective symptomatology improved in all patients and erythema extension, intensity and infiltration improved in 13 of 15 patients (87%). Treatment was well tolerated with no reported adverse events. Conclusions BoNTA therapy resulted in improvements in subjective patient symptomatology and objective reductions in erythema and maceration in the treated areas according to photographic evidence. Further large‐scale methodologically rigorous studies are required to investigate the safety and efficacy of BoNTA in this indication.