Friend or foe? Sebaceous cyst inflammation during ixekizumab therapy in psoriatic arthritis: case based review

Ixekizumab is a monoclonal antibody used in the treatment of moderate-to-severe psoriasis and psoriatic arthritis by targeting interleukin-17 A (IL-17 A). It has demonstrated efficacy in controlling inflammation in autoimmune diseases, though adverse reactions can arise. This case study reports a case of 25-year-old female with psoriatic arthritis undergoing treatment with ixekizumab, who developed acute enlargement and inflammation of a pre-existing sebaceous cyst located posterior to the left auricle, occurring two days after the administration of a routine ixekizumab dose. The present study investigates the potential association between the inflammatory process observed within the cyst and the immunomodulatory mechanisms of ixekizumab. Literature review revealed no prior reports directly linking ixekizumab with sebaceous cyst inflammation. However, related adverse effects, including paradoxical inflammation, infectious complications, and immune dysregulation have been described in patients treated with IL-17 A inhibitors. These include IBD exacerbation, eczematous eruptions, paradoxical psoriasis, and rare systemic complications, suggesting broader immunological effects of IL-17 blockade.