A novel method to assess the potential role of sweating abnormalities in the pathogenesis of atopic dermatitis

Abstract

Although atopic dry skin is believed to be caused by defects in skin genes important for maintaining skin barrier function, the role of sweat in atopic dermatitis (AD) has been apparently underestimated. Given the great capacity of sweat to maintain and increase skin hydration, defective sweating responses may be a logical place to look for changes that predispose individuals to the disease. We investigated how disease process and sweating defects progress from early asymptomatic stages to the onset of clinically apparent disease by employing the impression mould technique, which allows an accurate quantification of individual sweat gland/duct activity in relation to skin surface topography. Insensible and sensible sweating responses under baseline conditions and after thermal stimulus, respectively, were measured in various stages of AD patients and healthy controls. In controls, under baseline conditions, sweat ducts/glands at the dermal folds secreted basal levels of sweat (insensible sweating), thereby maintaining skin hydration. Not only such insensible sweating but also sensible sweating markedly decreased even in the earliest asymptomatic stage and the decrease was followed by compensatory hyperhidrosis at the ridge: leakage of sweat into the dermis could represent the initial event resulting in the decreased sweating and inflammation. The defects eventually progressed involving all of the ducts/glands to develop systemic dry skin. AD skin is characterized by varying degrees of functional impairment of sweat ducts/glands depending on the stage, and this defect would be among the reasons for the inability of AD patients to maintain skin hydration.

Acute Exacerbation of Fever Following Administration of Tropicamide and Phenylephrine Ophthalmic Solution: A Case Report

“…Patients with atopic dermatitis often experience hypohidrosis and delayed perspiration [ 14 , 15 ]. It is also known that some patients with atopic dermatitis suffer from heat retention because of the lack of adequate perspiration.…”

A new era for translational atopic dermatitis research and management

“…After hardening, sweat droplets become visible in the silicone matrix and can be quantified, and their mean diameter can be assessed. Shimeda‐Komatsu et al demonstrate that the number of sweat droplets under baseline condition is reduced in the skin of patients with AD, while the diameter of droplets, however, is increased . These differences can still be detected after application of a thermal stimulus that promotes sweating.…”

“…The impression mould technique (IMT), which uses silicone material that is spread onto sweating human skin, is one such method . After hardening, sweat droplets become visible in the silicone matrix and can be quantified, and their mean diameter can be assessed.…”

“…In addition, dermcidin was used as a marker for sweat and sweat distribution, and the authors found a leakage of dermcidin into the tissue surrounding the sweat ducts in AD, supporting their theory of sweat‐induced inflammation. All in all, sweating defects observed in AD seem to be due to the dysfunctioning of sweat gland and/or ducts, and monitoring the ability to sweat in patients with AD may be of additional value, also when evaluating new therapeutic options …”

A case of atopic dermatitis with hypohidrosis improved after dupilumab treatment

“…1,2 AD is a known cause of hypohidrosis; however, the pathophysiological mechanism is unclear. 3,4 We presented a case of AD with hypohidrosis, and the symptoms of AD as well as the perspiration were improved after dupilumab treatment.…”