Scalp Psoriasis: Investigating the Efficacy of Current Treatments

Psoriasis is a chronic inflammatory disease that affects approximately 2% of the United States population and is characterized by demarcated, erythematous, and scaly plaques present on the skin.¹ Although several types of psoriasis exist, up to 79% of patients present with plaques on the scalp. Since there is no cure for this condition, topical medications are typically used to reduce symptoms. Unfortunately, the efficacy and safety of these agents has not been well established.

Scalp psoriasis is not only visible, and therefore often embarrassing for patients, but is also difficult to treat for several reasons.¹ First, hair can block the medication from reaching its site of action on the scalp. Second, the sensitive facial skin can also be exposed to these medications, thereby increasing the risk of adverse events from treatment. Finally, patients often consider these agents to be aesthetically unappealing, potentially leading to decreased patient compliance. Available therapies for scalp psoriasis are reviewed in Table 1. 

A recent meta-analysis assessed the efficacy and safety of available treatments for scalp psoriasis.¹ Three primary and three secondary outcomes were investigated. The primary outcomes were a decrease in disease severity measured by the Investigators’ Global Assessment of Disease Severity (IGA) scale or by calculating the change of the Total Severity Score (TSS) from baseline, an increase in quality of life, and adverse events that caused withdrawal from the study. The secondary outcomes were a decrease in disease severity according to the Patients’ Global Assessment of Disease Severity (PGA) scale, adverse events that did not cause withdrawal from the study, and the duration of time the patient responded to therapy or was disease-free.

Results from the meta-analysis determined that topical corticosteroids were the most effective treatment for scalp psoriasis.¹ One analysis found that high and very high potency corticosteroids increased the clearance of scalp psoriasis by 1.8 times and doubled the chance of a patient responding to therapy compared to treatment with vitamin D alone. Additional studies showed that a combination product of corticosteroid/vitamin D was more effective in achieving clearance of scalp psoriasis versus corticosteroid or vitamin D monotherapy. It is important to note that the combination product was only slightly superior in reducing disease severity versus corticosteroid monotherapy, therefore it was concluded that use of combination therapy may not be clinically beneficial.