Efficacy of Botulinum Neurotoxin Type A for Treating Recalcitrant Plaque Psoriasis

A 75-year-old Hispanic woman presented to a private Dermatology clinic with chronic mild-to-moderate plaque psoriasis (PASI 6.1) that had been treated in the past with 0.05% fluocinonide solution to the scalp, and 0.05% clobetasol propionate cream to the active lesions on the body. Multiple well-circumscribed ~1-6 cm white scaly plaques were concentrated on her elbows, forearms, scalp, upper back and gluteal region. The patient had been using topical steroid therapy intermittently on difficult to reach symptomatic plaques but complained about trouble seeing and reaching the plaque on her back/buttocks to apply topical steroids. She complained of itchiness and asked about alternative therapy options.

A clearly defined plaque was identified on the patient’s left buttock (Figure 1A) and was intradermally injected at 8 specific loci ~1cm apart spanning the width and length of the plaque (Figure 1B), with 3.75 units administered at each injection site (30 total units of abobotulinumtoxinA, Dysport^® (Medicis Aesthetics, Scottsdale, AZ). The off-label use of abobotulinumtoxinA to treat the patient did not require IRB approval, as it was not initiated as a research study. No cutaneous or muscular adverse events were noted at the time of injection or during the follow-up period. Within three weeks of injection, the patient reported an improvement in plaque severity and complete remission of the treated lesional plaque was noted and sustained until 7 months post-injection (Figure 1C). During the 7-month follow-up, other plaques persisted and new plaques developed (not shown). At 8 months post-injection, the lesion recurred in the same location (Figure 1D). Concurrent with this, the patient experienced an unrelated outbreak of cutaneous HSV on her right buttock at a previously established site (Figure 1D).

There have been numerous reports of psoriasis remission following nerve injury, nerve blockade, or loss of innervation, ^4-8 suggesting a contributory role for cutaneous nerves in sustaining psoriasis pathogenesis. Recently, we identified the importance of cutaneous sensory nerves, specifically nerve-derived CGRP and SP in sustaining psoriasiform skin inflammation in the KC-Tie2 mouse model, by surgically eliminating the nerves or pharmacologically inhibiting these peptides.⁹ Botulinum neurotoxin type A (BoNTA) is best known for its inhibition of cholinergic neurotransmission at the neuromuscular junction, however it is equally efficacious at inhibiting nerve-derived release of SP and CGRP.¹⁰ We recently validated the ability of a single intradermal injection of BoNTA to exert similar levels of phenotype improvement.³ Two prior reports have suggested that onabotulinumtoxinA (BOTOX^®) can improve inverse psoriasis of the axilla and inframammary regions^1,2 at doses between 50-100 total units/site. Here, we report local plaque remission with a single intradermal treatment of abobotulinumtoxinA (Dysport^®) totaling 30 units, the equivalent of ~10-15 units of onabotulinumintoxinA (BOTOX^®). To our knowledge, this the first report of efficacy in psoriasis patients of abobotulinumtoxinA-induced skin improvement. This is similar to our prior observations of local skin improvement following intradermal injection in the KC-Tie2 mouse, wherein a single injection lead to disease improvement within 2 weeks, concurrent with decreases in CD4+ and CD11c+ skin-infiltrating immune cells.³

The observed timeframe for psoriasis improvement and recurrence are similar to what is known regarding cosmetic use of BoNTA, specifically with respect to glabellar line improvement following intramuscular injection at similar doses (20U).¹¹ However the onset of improvement and the duration of action are