In the 6 cases we reviewed, the time from starting secukinumab to onset of vasculitis ranged from 1 to 18 months. Our patient’s same-day re-emergence of vasculitis after his first secukinumab dose was so acute that we were skeptical of secukinumab as a potential trigger; this may simply have been coincident to the natural waxing and waning of the vasculitis (although onset of IgA vasculitis within 1 day of starting anti–TNF-α therapy has been reported).1-6,13
Specific associations of IgA vasculitis are many and can include bacterial organisms such as Helicobacter pylori, streptococci, and staphylococci. Although internal mucous membrane infections are considered more linked because of the surveillance role of IgA predominantly in mucosal tissues, it is possible that our patient with cutaneous MRSA harbored the same within the nasal mucosa. Our patient also received multiple vaccinations outside our department throughout his clinical course (2 hepatitis B and 1 pneumococcal conjugate), which are known potential triggers for vasculitis. Psychological stress is a known trigger for psoriasis, and given the cytokinetic relationship of psoriasis to vasculitis described previously, it may have indirectly contributed to vasculitis in our case. The anxiety associated with being immunosuppressed during the COVID-19 pandemic and bereavement of losing a family member may have contributed to the refractory nature of our patient’s condition. Renal involvement is relatively common in adults with IgA vasculitis and so should be ruled out, as should occult internal malignancy.8,10,14
It is unclear which of the above factors was causative in our case, but a multifactorial process is likely. Treatment of monoclonal antibody–associated vasculitis entails investigating for triggers and systemic involvement, removing the most likely culprit, quelling the vasculitis acutely, avoiding known potential exacerbators, and introducing an alternative long-term immunomodulant. In all 6 reported similar cases, discontinuation of secukinumab and initiation of prednisone or colchicine led to resolution.1-6 Dapsone also is acceptable for acute control of IgA vasculitis, although this medication is highly lipid soluble and penetrates well into various tissues.15 Thus, lower doses may prove ineffective for obese patients, as was demonstrated in our case. Given the known potential of vaccinations, infections, and other factors (eg, alcohol, penicillin) to trigger IgA vasculitis, these should be avoided.10
Blockade of IL-23 with ustekinumab has been suggested by other authors encountering secukinumab-associated vasculitis, as IL-23 is the main driver and sustainer of TH17 cell differentiation.8 Although 6 previously reported cases of secukinumab-associated vasculitis achieved resolution without long-term recurrence, none did so using an IL-23 inhibitor (nor had any of the described patients received IL-23 inhibitors previously).1-6 Given the established safety of IL-23 inhibitors and that they theoretically are well suited for this unique circumstance (by ceasing the main causative cytokine cascades “upstream”) and were efficacious in quickly resolving our patient’s vasculitis, we suggest that ustekinumab may represent an ideal treatment option for patients in whom adalimumab- or secukinumab-associated vasculitis is suspected. Further research is needed given the complex interplay of so many variables and the increasingly common reports of adverse cutaneous events associated with these drugs.1-6,10