For patients with inflammatory dermatoses, applying an emollient and allowing it to dry before applying a topical corticosteroid (TCS) may be beneficial, as reported in study findings published in the Journal of the European Academy of Dermatology and Venereology.
The combined use of a TCS and emollient in the management of patients with inflammatory dermatoses can be difficult for patients and challenging for healthcare professionals regarding the sequence and time between application of the 2 products.
When vehicle ingredients from a TCS and an emollient product are combined during an application, an in situ formulation develops in a locally limited area. How well they mix depends on the physicochemical properties of the vehicle ingredients of both products, as well as the sequence and time between the applications, noted the researchers.
Study authors conducted an experiment to visualize the effect when a TCS and an emollient are combined on patients’ skin. When a TCS was applied first, a hydrophilic emollient could not dissolve the lipophilic TCS vehicle ingredients, and a lipophilic emollient was able to dissolve the lipophilic TCS vehicle very well. In the latter case, the TCS was administered over the full application area of the emollient, which is undesirable as it increases the application area and percutaneous absorption of the TCS. This finding applied to TCS cream and ointment.
“As TCS cream and ointment are both very lipophilic, the observation is thus independent of product format,” stated the researchers. “When hydrophilic or lipophilic emollients were applied first and then TCS, the latter remained locally.”
Results from the experiment showed that when 2 topicals are combined on a patient’s skin, even if 1 formulation has been “absorbed” or “dried up,” the subsequent formulation may redissolve the vehicle ingredients of the initially applied formulation. This finding depends on physicochemical characteristics such as hydrophilicity and lipophilicity of both formulations. In addition, vehicle designations are not appropriate to make recommendations, because they do not provide reliable indications for the physicochemical properties of the products and vehicle changes after application, according to the investigators.
“We recommend applying the emollient first and then — after a drying time of several minutes to allow evaporation of volatile ingredients — the TCS to prevent unnecessary distribution of TCS over skin areas larger than intended,” the researchers advised.
The order of application of a TCS and emollient did not appear to affect the treatment efficacy, noted the study authors.
“For practical reasons, it may be more convenient for patients to split product application according to the time of day (morning/evening),” the investigators stated. “Other application modalities may also be practical to increase patients’ adherence.”
Surber C, Robertis J, Reinau D. Topical corticosteroid (TCS) or emollient product: which to apply first? J Eur Acad Dermatol Venereol. Published online December 4, 2022. doi:10.1111/jdv.18797