Clinical benefit and tolerance profile of a keratolytic and hydrating shampoo in subjects with mild to moderate psoriasis. Results from a double‐blind, randomized, vehicle‐controlled study

Scalp psoriasis frequently goes with other disease location and may lead to a significant burden and impairment of quality of life (QoL). Adherence to local treatments is a frequent problem. A keratolytic and hydrating shampoo containing 2% salicylic acid, 5% urea, and 1% glycerin (active shampoo) has been developed for psoriasis‐prone scalp.


| INTRODUC TI ON
Psoriasis is a chronic, inflammatory skin disease that affects 2% of the global population. 1 Scalp psoriasis is estimated to affect up to 80% of patients with psoriasis and can lead to a significant burden and reduced quality of life (QoL). [2][3][4] It requires special consideration due to the difficult-to-treat nature and disproportionate impact QoL. 3,5,6 Moreover, due to its chronicity, poor accessibility, and poor cosmetic effect of topical treatments, adherence to local treatments is a frequent problem. 7,8 Treatments mainly rely on topical steroid-based formulations that can lead to skin irritation (especially hydroalcoholic lotions) during the short term and to local adverse events during long term use. A keratolytic and hydrating shampoo (PSOlution, Laboratoires Vichy International, France, hereafter "active shampoo") containing 2% salicylic acid, 5% urea, and 1% glycerin, acting on psoriasis symptoms has been developed for psoriasis prone scalp.
The aim of this study was to assess in subjects with mild-tomoderate scalp psoriasis, the efficacy and local tolerance of an active shampoo.

| MATERIAL S AND ME THODS
A single-center, randomized, double-blind, vehicle-controlled study was conducted in adult subjects with mild-to-moderate psoriasis who applied the active shampoo or its vehicle daily for 2 minutes Subjective data were submitted to a binomial test.

| DISCUSS ION
Results from this double-blind, randomized study showed that a non-medicated shampoo containing keratolytic and hydrating agents significantly (all p < 0.05) improves the PSSI, IGA, and psoriasis-related symptoms of subjects with mild to moderate scalp psoriasis compared to its vehicle within 2 weeks of daily application followed by a 3 times/week use while studies showed that a shampoo containing LHA significantly improved scalp psoriasis or scalp dermatitis only after 4 weeks of treatment. 9,10 Similar were only obtained when using shampoos that contain corticosteroids or tar in moderate to severe scalp psoriasis over 4 weeks. 11 The present beneficial outcome with the tested shampoo is particularly important as the continuous use of pharmacologically active formulations to treat scalp psoriasis, especially corticosteroids is not recommended. Due to this restriction of use, regular treatment-free periods are mandatory in order to reduce or to prevent corticosteroids-related side effects. 12 As a consequence, treatment-free periods may result in the relapse of psoriasis, requiring another treatment period going along with a novel risk of treatment-related side effects. Thus, using a non-medicated shampoo to maintain the treatment success of pharmacologically treated mild-to-moderate scalp psoriasis during the treatment-free period may reduce treatment cycles or increase the delay between such courses. Moreover, the shampoo may be indicated in the management of milder forms of scalp psoriasis, without any restriction. The excellent local tolerance of the tested active shampoo may help to improve adherence to care, thus prolonging the treatment-free period even further.
Unfortunately, the study did not show any differences between the active shampoo and the vehicle concerning QoL which may be due to the highly appreciated vehicle formulation-that also serves as the basis for the active shampoo. This formulation contains glycerin which is known to improve skin hydration, improving skin dryness, signs, and symptoms going along with the latter. As a result of improved skin dryness, subjects may experience an improved quality of life through a decreased burden, as with any other emollient, moisturizer, or hydrating rinse-off formulation.
As for all clinical studies, the present investigation has its limits. In addition to the rather small number of participants which did not allow for adjusting for SCALPDEX assessments, the study design may not reflect real-life use of the active shampoo; subjects may not apply the product on the hair for 2 min thus reducing its benefit leading to a potentially earlier relapse. Despite these issues, the study provided evidence that subjects who were successfully treated for the scalp psoriasis followed be the use of the tested active shampoo maintain the initial treatment outcome.
In conclusion, the tested keratolytic and hydrating shampoo improves mild to moderate scalp psoriasis. It is an interesting option in the daily care of this chronic inflammatory disease, alone or combined with local reference medications. F I G U R E 2 Improvement of the scalp over time with the active shampoo.