Erythrodermic psoriasis is a severe form of psoriasis, presenting as prominent erythema rather than thick scales, affecting the entirebody including the face, trunk, extremities, and nails. The disease poses a therapeutic challenge, and numerous treatment choices have been examined1.

Ustekinumab (Stelara; Jannssen Biotech Inc., Horsham, PA, USA) is a human monoclonal antibody targeting the p40 subunit shared by interleukin (IL)-12 and IL-23. This biological agent has shown good efficacy against plaque-type psoriasis and emerging effectiveness in a variety of inflammatory skin diseases such as atopic dermatitis2. Erythrodermic psoriasis has been an exclusion criterion in studies evaluating the efficacy of ustekinumab for psoriasis, but recently, a few reports have proven its efficacy in treating erythrodermic psoriasis345. Herein, we report 2 cases of erythrodermic psoriasis that successfully improved following ustekinumab treatment.

A 42-year-old man presented with a 7-year history of erythrodermic psoriasis and a 5-year history of psoriatic arthritis. He was previously treated with cyclosporine A, methotrexate, and narrow band ultraviolet B phototherapy. The treatments were interrupted due to liver enzyme elevation and low efficacy. The patient was treated with ustekinumab 45 mg subcutaneously at 0, week 4, and every 12 weeks thereafter. The patient was also diagnosed with latent pulmonary tuberculosis by the QuantiFERON-TB Gold In-Tube test (Cellestis Limited, Carnegie, VIC, Australia). He was concurrently treated with isoniazid 300 mg/day for 6 months and has not experienced a recurrence of tuberculosis to date. At week 28, his Psoriasis Area and Severity Index (PASI) score decreased from 64.8 (baseline) to 9.6 (Fig. 1). The psoriasis aggravated temporarily during discontinuation of the treatment for 5 months and he promptly recovered upon restarting ustekinumab injections. His arthritis symptoms improved slightly, but the improvement was not sufficient for him to stop taking oral sulfasalazine and steroid for the arthralgia.

The second case is a 26-year-old man suffering from erythrodermic psoriasis for 10 years. Therapies with conventional systemic agents and anti-tumornecrosis factor were discontinued due to lack of efficacy. Four months after the first administration of ustekinumab (45 mg), the patient achieved 75% improvement of the PASI score from 50.9 (baseline) to 4.4 (Fig. 2A, B). Currently, the patient has received treatment for 112 weeks, and is maintaining a PASI 90 improvement (Fig. 2C).

Both patients are currently on treatment, and show sustained responses without any adverse reactions or exacerbations. Although further studies are needed to evaluate the efficacy and safety of ustekinumab, it is likely that ustekinumab can be an effective therapeutic option for patients affected by erythrodermic psoriasis where other treatments have failed.