Effects of a moisturizer containing pseudo‐ceramide and a eucalyptus extract on sweating function in adult atopic dermatitis: a double‐blind, randomized, controlled left‐right comparison clinical trial

Abstract Background Many patients with atopic dermatitis (AD) have a decreased ability to sweat. Several factors can cause decreased perspiration, such as weak tight junctions of sweat ducts, reduced acetylcholine receptor function, and inhibition of perspiration by histamines. Parakeratosis of AD skin also decreases sweating by occluding sweat pores. Increased ceramide levels in the stratum corneum reduce parakeratosis by improving stratum corneum functions. Furthermore, ceramides and/or ceramide derivatives may affect claudin‐3 and acetylcholine receptors. Objective In this study, we investigated the efficacy of a moisturizer containing pseudo‐ceramide and a eucalyptus extract to increase ceramide levels in the epidermis to improve the sweating ability of patients with AD. Methods Nineteen patients with AD applied moisturizers with or without pseudo‐ceramide and a eucalyptus extract on the cubital fossa of either arm twice a day for 4 weeks. Skin conditions and sweating ability, measured as the response to acetylcholine stimulation, were evaluated prior to the start of the study (Week 0) and at the end of Weeks 2 and 4. Results Both moisturizers improved the visually evaluated skin symptoms and skin hydration. However, only the moisturizer containing pseudo‐ceramide and the eucalyptus extract significantly improved cutaneous barrier function and significantly increased the ceramide level in the stratum corneum. That moisturizer also increased the sweating volume and shortened the latency time for sweating, an indicator of sweating ability, but the other moisturizer did not. Conclusion Based on these results, the moisturizer containing pseudo‐ceramide and a eucalyptus extract helps recover the sweat function of AD patients.