The ‘acid mantle’ of the stratum corneum seems to be important for both permeability barrier formation and cutaneous antimicrobial defense. However, the origin of the acidic pH, measurable on the skin surface, remains conjectural. Passive and active influencing factors have been proposed, e.g. eccrine and sebaceous secretions as well as proton pumps. In recent years, numerous investigations have been published focusing on the changes in the pH of the deeper layers of the stratum corneum, as well as on the influence of physiological and pathological factors. The pH of the skin follows a sharp gradient across the stratum corneum, which is suspected to be important in controlling enzymatic activities and skin renewal. The skin pH is affected by a great number of endogenous factors, e.g. skin moisture, sweat, sebum, anatomic site, genetic predisposition and age. In addition, exogenous factors like detergents, application of cosmetic products, occlusive dressings as well as topical antibiotics may influence the skin pH. Changes in the pH are reported to play a role in the pathogenesis of skin diseases like irritant contact dermatitis, atopic dermatitis, ichthyosis, acne vulgaris and Candida albicans infections. Therefore, the use of skin cleansing agents, especially synthetic detergents with a pH of about 5.5, may be of relevance in the prevention and treatment of those skin diseases.

European Union; German Centre for Infection Research; German Research Council; and German Ministry for Education and Research.

A single-point mutation in exon 15 of the BRAF gene has recently been reported in a high percentage in cultured melanoma cells and in 6 of 9 primary melanomas examined. To evaluate the impact of the T1796A BRAF mutation, we screened primary melanomas, various types of nevi and lesions where a melanoma developed in an underlying nevus. We could detect the mutation in 28 of 97 (29%) melanomas and in 39 of 187 (21%) nevi, including blue nevi (0/20) and Spitz nevi (0/69), which did not carry the mutation. In melanomas with an underlying nevus, either the mutation was present in both the laser-microdissected nevus cells and the laser-microdissected melanoma cells (3/14) or both lesions were negative for the BRAF mutation except one case. In conclusion, mutations in exon 15 of the BRAF gene are nonspecific for progression of a nevus to a melanoma. Other so far unknown cofactors seem to be of importance.

No abstract

As a noninvasive diagnostic method, real-time B-mode sonography belongs to the diagnostic standard procedures in various fields of clinical medicine, for example, internal medicine, gynecology, and otorhinolaryngology. During the past 3 decades, ultrasound technology has been extended to clinical dermatology. High-frequency ultrasound systems with 20- to 50-MHz probes are used for the assessment of tumoral and inflammatory processes of the skin, providing information about their axial and lateral extension. They are of special interest in preoperative situations and for the monitoring of skin conditions under therapy. In contrast to high-frequency ultrasound systems, the value of ultrasound technology with the use of 7.5- to 15-MHz probes generally is not accepted worldwide, although it can be used easily and without significant side effects. Promising results have been reported from specialized diagnostic centers, especially for the assessment of peripheral lymph nodes and soft-tissue tumors. Although it is unable to provide malignancy specific information, ultrasound is nonetheless helpful in the follow-up of patients undergoing, for example, chemotherapy or radiotherapy. The 3-dimensional size and outline of a tumor as well as its relation to surrounding structures like vessels can be described. Moreover, information about the tumor quality (solid, cyst, complex) and the inner structure of a tumor (hypoechoic, hyperechoic, homogenous, inhomogenous, calcification foci, necroses) can be provided. In addition to conventional B-mode-sonography, newer ultrasound techniques like native and signal-enhanced color Doppler sonography as well as ultrasound-guided fine needle aspiration cytology are reviewed.