Atopic dermatitis exacerbated with ustekinumab in a psoriatic patient with childhood history of atopy

Ustekinumab is a biological agent that is currently approved for the treatment of moderate to severe plaque psoriasis. It is a monoclonal antibody that binds the p40 subunit of IL-12 and IL-23 to limit the progression of the Th1 and Th17 inflammatory immune responses. Recently, it has been suggested that ustekinumab could represent a potential treatment for atopic dermatitis (AD).1e3 However, inadequate response to ustekinumab in AD patients has also been reported.4 We present a case of paradoxically exacerbated AD during the ustekinumab treatment for psoriasis. A 21-year-old man with a 7 year history of severe psoriasis refractory to conventional systemic treatments and childhood history of atopy (atopic dermatitis-AD, asthma, seasonal rhinitis) was treated with ustekinumab. The patient was without major symptoms from respiratory system and AD lesions within a period of 5 years before the date of starting the treatment. He was taking montelukast, antihistamines, inhaled corticosterois and formoterol for asthma. Psoriatic lesions and no clinical sings of AD were found on baseline examination (Fig. 1). Ustekinumab 45 mg (1 injection at week 0 and week 4, then every 12 weeks) was introduced (according to body weight: 76 kg). After 18 months and following excellent results, the patient decided to discontinue therapy. But 8 months later recurrence of psoriasis was observed and ustekinumab was restarted. The baseline PASI fell from 11,4 to 3,0 after 4 weeks of treatment with ustekinumab, complete remission of psoriasis was achieved after 8 weeks of therapy. However, intense generalized itching occurred since the first dose was administered. Severe AD appeared on the neck and lower limbs about 6 weeks after the reintroduction of ustekinumab (Fig. 2). Eczematous drug eruption and AD exacerbation due to stress, infection, or other external factors (i.e. topical treatments of psoriasis) was excluded in the differential diagnosis. Apart from dermatologic findings, physical examination revealed no abnormalities. Laboratory tests showed peripheral blood eosinophilia (1,48 109/L, compared to the baseline of 0,46 109/L, to the 16 weeks of 0,58 109/L, to the 28 weeks of ustekinumab therapy of 0,67 109/L, and to the recurrence of psoriasis of 0,66 109/L), as well as abnormal increase in serum allergen-specific immunoglobulin E (sIgE) level including dog-, cat-, hamster-, and grass pollen-specific IgE. Total IgE level was 12576 IU/ml (0e100,0 IU/l reference range). Other laboratory data (erythrocyte sedimentation rate, C-reactive protein level, complete blood count, biochemical parameters of liver and kidney, urinalysis) were normal at several time points. Spirometry