Scalp psoriasis and biologic agents: a retrospective, comparative study from a tertiary psoriasis referral centre.

Background The scalp is a frequent and difficult-to-treat localization of psoriasis. Little evidence exists regarding the use of biologic agents in recalcitrant cases of scalp psoriasis that are resistant to other treatment options. Objectives To evaluate and compare the efficacy of currently available biologic agents (infliximab, etanercept, adalimumab, ustekinumab) in the treatment of scalp symptoms in patients suffering from moderate to severe plaque psoriasis. Materials and methods This retrospective cohort study consisted of a review of the database of all psoriasis patients who suffered from scalp symptoms and received biologic treatment between January 2012 and December 2014. The patients were divided into four groups based on the drug administered. Scalp psoriasis severity was assessed by the Psoriasis Scalp Severity Index (PSSI) at baseline and at weeks 4, 12, 24 and 48. Psoriasis severity was evaluated with the Psoriasis Area and Severity Index (PASI) at the same time points. Results In total, 145 patients were enroled in the study (infliximab n = 35, etanercept n = 30, adalimumab n = 39, ustekinumab n = 41). At week 4, the infliximab group achieved a 74% mean decrease in the PSSI (ΔPSSI), followed by mean decreases of 61.7%, 53.1% and 53.7% in the ustekinumab, etanercept and adalimumab groups respectively. The differences in the ΔPSSI were lower at week 48: ustekinumab 94.9%, infliximab 94.3%, etanercept 83.1% and adalimumab 89.0%. The PASI score improved sufficiently in all treatment groups. Infliximab and ustekinumab exhibited greater efficacy at weeks 4 and 12. This difference was not as prominent as that revealed by the PSSI. At week 48, the differences in the ΔPASI were barely statistically significant (P = 0.048). Conclusions All four biologic agents yielded significant improvement in both scalp and skin lesions. Ustekinumab and infliximab exhibited the greatest efficacy, which was clinically meaningful from the early stages of the study. Adalimumab and etanercept followed, yielding satisfactory improvement rates.