Psoriasis vulgaris is a chronic immune-mediated inflammatory disease of the skin. Biologic therapy has been available for more than ten years and has become one of the standard treatments for patients with moderate to severe psoriasis.
Firstly, drugs against tumour necrosis factor alpha (TNF-α) were used and only later drugs against different interleukins (IL) like 17 or 23 became available. Side effects of biologic therapy include paradoxical adverse events (PAE) like palmoplantar pustular reaction, especially with anti-TNF-α drugs.
We present a case of a 49-year old female diabetic patient with psoriasis and psoriatic arthritis treated with an adalimumab biosimilar who developed a severe PAE of the palmoplantar pustular type. Adalimumab was stopped and the patient was switched to ixekizumab which was successful.
When a paradoxical reaction develops during biologic therapy, especially when it is severe like in our patient, switching to another class of biologics is advised.