Pruritus intensity, psoriasis severity often not correlated

Targeted antipruritic therapies are needed for patients with psoriasis and other dermatologic conditions, according to recent letter to the editor published in the Journal of American Academy of Dermatology.

Previous reports in the literature suggest an estimated 70% of patients with psoriasis have at least moderate pruritus and there are conflicting reports regarding a link between pruritus intensity and psoriasis disease severity. In addition, impact of topical corticosteroids and vitamin D analogs on pruritus in psoriasis has not been effectively studied.

David Roblin, MD, FRCP, from Creabilis Ltd. in the United Kingdom, and colleagues from Temple University, Philadelphia, reported on data for 157 patients with mild to moderate psoriasis based on the Investigator Global Assessment and a mean modified Psoriasis Area Severity Index (mPASI) score of 8.9.

Overall, 98 patients in the study had pruritus; 68.8% had at least moderate pruritus (visual analog scale [VAS] score ≥ 40 mm) and 33.8% severe pruritus (VAS score ≥ 70 mm).

Using these data, the researchers explored the potential relationship between pruritus, measured by VAS, and psoriasis disease severity, measured by mPASI. Based on the coefficient of determination (R2) value, only 3.8% of the variability in pruritus severity can be explained by its relationship to disease severity as measured by mPASI.

“As mPASI measures inflammatory-mediated aspects of psoriasis, this lack of correlation suggests that treating pruritus in patients with psoriasis with anti-inflammatory agents may be a suboptimal approach,” the study authors wrote. “The lack of correlation between pruritus severity and psoriasis disease severity that we have observed, coupled with the high prevalence of pruritus and unmet need, warrants greater attention to pruritus by clinicians and researchers to develop targeted antipruritic therapies for patients with psoriasis and other dermatologic conditions.”