Suchergebnisse

Although the acidic surface pH of the skin has been known for over a century, the stratum corneum (SC) pH gradient has been discovered only recently. After removal of SC layers with sequential tape strips, in humans, surface pH starts at 4.5–5.3, increasing by about 2–3 units until it reaches 6.8 in the lower SC. Both exogenous [free fatty acids (FFA) from sebaceous lipid, microbial metabolites, lactic acid from eccrine glands] and endogenous epidermal (enzymatic; membrane antiporters/pumps) mechanisms have been hypothesized to contribute to SC acidification. Three endogenous mechanisms have been identified to date that not only could influence SC pH, but also regulate one or more key SC functions: (1) the histidine-to-urocanic-acid pathway; (2) the phospholipid-to-FFA pathway, and (3) the sodium proton antiporter (NHE1). Additional factors that influence human surface pH have been detected. Endogenous factors, unrelated to pathological features, such as racial differences, topographical variation, gender differences, developmental and age-related changes have been reported. In contrast to adults, human newborn SC displays a near-neutral surface pH, which declines rapidly over the first postnatal month. Furthermore, endogenous factors have been described, as in atopic dermatitis, seborrheic dermatitis, diabetes, renal insufficiency and ichthyosis associated with an increased pH. Exogenous factors, like the use of detergents and cleansing products as well as SC hydration, can modify the surface pH. The consequences of SC acidification for several key SC functions are becoming clear, including (1) the role of an acidic pH for SC permeability barrier homeostasis, (2) the pH dependence of extracellular lipid processing and (3) SC integrity/cohesion. Integrity is defined as a measure of resistance to dissociation of adjacent corneocytes by tape stripping (cohesion is a related index defined as the amount of protein removed per stripping). (4) Proteolytic processes leading to desquamation are pH dependent, and (5) an acidic pH provides important antimicrobial resistance.

The French government imposed the first COVID-19 pandemic lockdown from March 17 until May 11, 2020. Only emergency cases and teledermatology (TD) were allowed in outpatient settings. A standardized questionnaire was developed to compare the satisfaction level of patients and their treating physicians. Our main question was whether the patients would perceive TD as a valid alternative for direct physical face-to-face consultation. Eighty-two patients and their 4 treating dermatologists from one dermatology department participated in the study (43 females, 39 males) with a mean age of 46.6 years (SD ±23.9). The reason for TD was a chronic disease in the majority (87.8%), and mainly as a follow-up (96.3%). Regarding satisfaction, almost all categories rated around 9 on a 0–10 verbal analogue scale. The same level of global satisfaction could be seen between the patients and the physicians as well as for the quality of the patient-physician relation and whether all questions could be addressed during the TC. Physicians showed significantly higher scores than patients only for the category of "length" of the consultation. Gender, age, as well as distance between the clinic and home of the patient were not influencing factors for satisfaction. Regarding the technical parameters, the evaluation was mostly comparable for patients and physicians, but overall lower than the relational satisfaction parameters, especially for image quality. Patients were significantly more motivated to continue the TD after the lockdown than their treating dermatologists. We see an interest for implementing TD in specialized centers with chronic patients coming from remote places for regular follow-ups. TD cannot replace in-person patient-physician interaction, but was helpful during the lockdown. As a result, TD might become part of dermatology training to prepare for future lockdown situations.