Could Psoriasis Therapy Increase Herpes Zoster Risk?

Taking biologic medications in combination with methotrexate to treat psoriasis was linked to an increased risk for developing herpes zoster (HZ), according to a recent study.

In the past, studies have focused on how corticosteroids and old age link to HZ manifestation, but researchers have seldom examined HZ risk in those with psoriasis who were treated with biologic medications or other systemic treatments.
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Over a follow-up of 11 years and 7 months, researchers calculated HZ incidence in 95,941 patients with psoriasis.

In order to evaluate the impact of each systemic treatment use to treat psoriasis, researchers used a generalized estimating equation Poisson regression model. They adjusted for sex, age, severity of psoriasis, steroid treatment, socioeconomic status, and Charlson comorbidity index.

The study showed that methotrexate, cyclosporine, and biologic medications used alone for psoriasis treatment did not cause HZ in patients.

In contrast, researchers discovered that the use of combination treatment (biological medications and methotrexate) yielded a heightened risk of HZ in patients (RR, 1.66).

According to investigators, a heightened risk of HZ was associated to the additive immunosuppressive effect of the biologic medications and methotrexate or the drug interaction increased the biologic medication blood levels.

The researchers further noted that acitretin treatment was linked to a decreased risk for developing HZ (RR, 0.69).

“This protective effect [from acitretin treatment] was not reported previously, and additional observations are needed to confirm this finding,” said the study’s authors.

“We assume that the protective effect may be related to psoriasis amelioration with minimal immunosuppressive effect of the drug compared with other treatment modalities in our model,” they said.

The complete study is published in the March issue of JAMA Dermatology.

-Michelle Canales Butcher

Reference:

Shalom G, Zisman D, Bitterman H, et al. Systemic therapy for psoriasis and the risk of herpes zoster. JAMA Dermatol. 2015 March [epub ahead of print] doi: 10.1001/jamadermatol.2014.4956.