Among patients with psoriasis treated with biologics, those receiving interleukin-23 inhibitors had the lowest risk of developing paradoxical eczema; women, older patients, and those with a history of atopic dermatitis or hay fever had an increased risk.

Among patients with psoriasis treated with biologic agents, the risk of developing paradoxical eczema was lowest among those treated with interleukin (IL)-23 inhibitors, according to study results published in JAMA Dermatology.

Use of biologics for the treatment of psoriasis may cause paradoxical eczema, which can result in treatment discontinuation or the need to switch to other immunosuppressants. Therefore, investigators conducted a prospective cohort study to determine the clinical and demographic risk factors of paradoxical eczema as well as the overall incidence and biologic-class-specific risk factors and incidence of paradoxical eczema among these patients. They sourced data from the British Association of Dermatologists Biologics and Immunomodulators Register (BADBIR).

The researchers analyzed data from 13,699 patients aged 18 years and older, representing a total of 24,997 biologic exposures. The median age of patients was 46 years, and 57% were men. The majority (92%) of patients were White, 6% were South Asian, 2% were “other,” 0.7% were Chinese, and 0.6% were Black.

There were 265 cases of paradoxical eczema linked to 273 biologic exposures and affecting 241 individuals. Symptom onset occurred at a median of 294 (IQR, 120-699) days after biologic treatment initiation, with the most common affected areas being the face and neck (26%), limbs (23%), trunk (13%), and hands or feet (12%). Patient symptoms included pruritus (18%), redness (7%), and dryness (4%).

Patients treated with IL-23 inhibitors were associated with a lower risk for paradoxical eczema than those treated with tumor necrosis factor inhibitors (hazard ratio [HR], 0.39; 95% CI, 0.19-0.81). However, no such association was found for IL-12/23 inhibitors (HR, 0.87; 95% CI, 0.66-1.16) or IL-17 inhibitors (HR, 1.03; 95% CI, 0.74-1.42).

Men had a lower risk of developing paradoxical eczema (HR, 0.60; 95% CI, 0.45-0.78), compared with women. However, the risk for paradoxical eczema was increased with age per year from age 18 years (HR, 1.02; 95% CI, 1.01-1.03), particularly among patients aged 50 to 69 years (HR, 1.75; 95% CI, 1.02-2.98) and those aged 70 years and older (HR, 2.52; 95% CI, 1.23-5.20). There was also an increased risk among patients with a history of atopic dermatitis (HR, 12.40; 95% CI, 6.97-22.06) and those with hay fever (HR, 3.78; 95% CI, 1.49-9.53). No association was found for asthma (HR, 0.97; 95% CI, 0.61-1.54). Additionally, patients of Chinese ethnicity experienced an increased risk for paradoxical eczema (HR, 2.81; 95% CI, 1.10-7.18).

Study limitations include the small number of observations with specific subgroups, a small number of paradoxical eczema events, and the risk that some adverse events were misclassified.

The researchers concluded, “In this study, there was a lower risk of paradoxical eczema among participants receiving IL-23 inhibitors.” They added, “Factors associated with paradoxical eczema included increasing age, female sex, history of AD, and history of hay fever. Future studies with more exposures and paradoxical eczema events would enable a more robust analysis of individual drugs and patient subgroups.”