Ustekinumab induces rapid clearing of erythrodermic psoriasis after failure of antitumour necrosis factor therapies

Conflicts of interest: none declared. Madam, Erythrodermic psoriasis (EP) is a severe form of psoriasis. Several drugs are effective in controlling EP, but some patients do not respond. Controlled trials have shown ustekinumab to be an effective and fast‐acting treatment for psoriasis.1, 2 A Medline search showed no case reports of EP treated with this new drug. We used ustekinumab to treat two patients with EP. Both had received previous systemic therapies (Table 1) and clinical and laboratory investigations were performed to exclude active tuberculosis and possible systemic infections. Antinuclear antibodies (ANA) and antidouble‐stranded DNA (anti‐dsDNA) antibodies were tested in the sera of the patients prior to starting biologic therapies and prior to commencement of ustekinumab treatment. Patient 1, a 32‐year‐old woman with a 22‐year history of chronic plaque psoriasis suboptimally controlled with oral ciclosporin, narrowband ultraviolet (UV) B and psoralen + UVA (PUVA) therapies and methotrexate, was commenced on weekly efalizumab 1 mg kg−1 administered subcutaneously. Five months later, she developed psoriatic arthritis [Disease Activity Score (DAS 44) of 6·2] and treatment with etanercept 50 mg twice weekly via subcutaneous injections was begun. Her psoriasis worsened and she had a Psoriasis Area and Severity Index (PASI) score of 37. The medication was changed to intravenous infliximab 5 mg kg−1 at 0, 2, 6 and 14 weeks. After 14 weeks she remained erythrodermic with a PASI score of 37. The patient was then changed to subcutaneous adalimumab 40 mg per 10 days. Eight weeks later the psoriasis remained stable with a PASI score of 37 and a DAS 44 score of 6·0. At this time ANA and anti‐dsDNA antibodies showed values of 1/320 and 1/320. No wash‐out period was given between the switch of biologic agents. Treatment with ustekinumab 40 mg subcutaneously was begun and 4 weeks later a dramatic improvement was seen: the patient achieved a PASI score of 7 (81% PASI improvement at 4 weeks) and a DAS 44 score of 1·9. A second dose was administered 4 weeks later and 3 months after the initial dose the PASI score was 1 (97% PASI improvement at 12 weeks). Arthritic symptoms improved (DAS 44 score of 1·6). At this time the values of ANA and anti‐dsDNA antibodies remained the same.