Although the precise underlying pathomechanisms of psoriasis have not been fully elucidated, previous reports suggest that T helper 1-type cytokines are critically involved in the pathogenesis of this disease. Interleukin-12 (IL-12), a heterodimeric cytokine, has been suggested to play a major role in the development of T helper 1 cell responses. In this study, the presence of IL-12 mRNA and protein was investigated in normal human skin as well as nonlesional and lesional psoriatic skin. Messenger RNA levels were determined in biopsy specimens by a standard and a nested reverse transcriptase-polymerase chain reaction method. Additionally, IL-12 protein expression was analyzed in situ by immunohistochemistry using an antibody recognizing IL-12 p70. Whereas specific transcripts for IL-12 p35 were reproducibly detected without any significant differences in all samples, enhanced IL-12 p40 mRNA signals were only found in lesional psoriatic skin as compared with normal and nonlesional psoriatic skin. Furthermore, immunoreactivity for IL-12 p70 was markedly increased in the psoriatic skin lesions and was predominantly expressed on mononuclear cells in the dermis. In conclusion, our data suggest a critical role for IL-12 in promoting and maintaining T cell activation and inducing T helper 1-type cytokines such as interferon-gamma in psoriasis. We speculate that IL-12 might be a key cytokine in the pathogenesis of psoriasis.

Factors associated with the detection of cutaneous melanomas and reasons for delay in diagnosis were investigated in 429 patients with histologically proven melanoma operated on between January 1993 and June 1996. Patients were interviewed using a standardized questionnaire. In 25% of patients, treatment was delayed for more than 1 year from the time they first noticed a suspicious pigmented lesion. Melanoma was detected by the patients themselves in 67% of women and 45% of men. The three predominant clinical symptoms of melanoma were change in colour (darker), increase in size and increase in elevation of a pigmented lesion. The role of sun exposure and of naevi as risk factors for melanoma, as well as the potential benefit of early treatment, were known by 87%, 66% and 82% of the patients, respectively. However, melanoma awareness had no impact on the time period between first observation of skin changes and treatment. Among the factors associated with delay in melanoma diagnosis, an initial incorrect diagnosis as a benign lesion by the physician first visited (in 18% of all cases) had the highest significance. Patients detecting their lesions themselves were treated significantly later than patients in whom others had remarked on changes in a naevus. Furthermore, melanomas of the head and neck were treated later than melanomas at other body sites. Further efforts to educate both the public and the medical profession are essential to ensure earlier treatment for cutaneous melanomas.

Actinic keratosis (AK) affects millions of people worldwide, and its prevalence continues to increase. AK lesions are caused by chronic ultraviolet radiation exposure, and the presence of two or more AK lesions along with photodamage should raise the consideration of a diagnosis of field cancerization. Effective treatment of individual lesions as well as field cancerization is essential for good long-term outcomes. The Swiss Registry of Actinic Keratosis Treatment (REAKT) Working Group has developed clinical practice guidelines for the treatment of field cancerization in patients who present with AK. These guidelines are intended to serve as a resource for physicians as to the most appropriate treatment and management of AK and field cancerization based on current evidence and the combined practical experience of the authors. Treatment of AK and field cancerization should be driven by consideration of relevant patient, disease, and treatment factors, and appropriate treatment decisions will differ from patient to patient. Prevention measures and screening recommendations are discussed, and special considerations related to management of immunocompromised patients are provided.

Rosacea (in German sometimes called 'Kupferfinne', in French 'Couperose' and in Italian 'Copparosa') is a chronic and frequently relapsing inflammatory skin disease primarily affecting the central areas of the face. Its geographic prevalence varies from 1% to 22%. The differential diagnosis is wide, and the treatment is sometimes difficult and varies by stage of rosacea. For erythematous lesions and telangiectasia, intense pulsed light (IPL) therapy and lasers are popular treatment option. In addition, a vasoconstrictor agent, brimonidine, has recently been developed. For papulopustular rosacea, topical antibiotics, topical and systemic retinoids, as well as systemic antibiotics are used. A topical acaricidal agent, ivermectin, has undergone clinical development and is now on the market. In the later stages, hyperplasia of the sebaceous glands develops, resulting in phymatous growths such as the frequently observed bulbous nose or rhinophyma. Ablative laser treatments have largely replaced classical abrasive tools. Here, we reviewed the current evidence on the treatment of rosacea, provide a guideline (S1 level) and discuss the differential diagnosis of rosacea.