Rosacea is a common chronic cutaneous disorder of unknown etiology which occurs most commonly in middle-aged individuals. Cutaneous manifestations include transient or persistent facial erythema, telangiectasia, edema, papules and pustules that are usually confined to the central portion of the face. The National Rosacea Society’s Expert Committee on the Classification and Staging of Rosacea identified four subtypes of rosacea: erythematotelangiectatic, papulopustular, phymatous and ocular. Recently, a standard grading system for assessing gradations of the severity of rosacea has been reported. Little is known about the cause of rosacea. Genetic, environmental, vascular, inflammatory factors and microorganisms such as Demodex folliculorum and Helicobacter pylori have been considered. Topical metronidazole and azelaic acid have been demonstrated to be effective treatments for rosacea. Severer or persistent cases may be treated with oral metronidazole, tetracyclines or isotretinoin.

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Summary Diseases of the male genitalia range from infectious lesions to inflammatory and neoplastic conditions, including many genital manifestations of more general skin diseases. This review highlights the clinical features, diagnosis and treatment of the most common dermatoses of the male genitalia. Herpes genitalis and infections caused by human papillomavirus (HPV) are increasing, particularly in young sexually active people. Herpes simplex virus infection is the commonest infectious cause of genital ulceration, with evidence that many infections are asymptomatic. HPV infection may be latent, subclinical and clinical. The most common causal agents for condyloma acuminatum are low‐risk HPV 6 and 11; high‐risk HPV types 16 and 18 are associated with premalignant and malignant lesions. Treatment for genital warts remains unsatisfactory; recurrences are common. Imiquimod, a new topical immunotherapeutic agent, which induces interferon and other cytokines, has the potential to be a first‐line therapy for genital warts. Scabies and pediculosis are transmitted by skin‐to‐skin contact and sexual transmission is common, with the penis and scrotum favourite locations for scabious lesions. Oral ivermectin, a highly active antiparasitic drug, is likely to be the treatment of choice, but until approval is granted it should be reserved for special forms of scabies. Common skin diseases, e.g. psoriasis and lichen planus, may have an atypical appearance in the genital area. The typical psoriatic scale is usually not apparent because of moisture and maceration. Allergic contact dermatitis of the genital area may result from condoms, lubricants, feminine hygiene deodorant spray and spermicides. More often, contact dermatitis is irritant, resulting from persistent moisture and maceration. Lichen sclerosus is a chronic inflammatory disease that occurs as atrophic white patches on the glans penis and foreskin. The penile form is a common cause of phimosis in uncircumcised men; involvement of the urethral meatus may lead to progressive meatal stenosis. Plasma cell balanitis is a benign, idiopathic condition presenting as a solitary, smooth, shiny, red‐orange plaque of the glans and prepuce of a middle‐aged to older man. Squamous cell carcinoma (SCC) in situ, e.g. erythroplasia of Queyrat and Bowen's disease, cannot be excluded clinically; their apparent clinical benignity may lead to lengthy periods of misdiagnosis and biopsy is required to confirm the diagnosis. SCC is the most common malignancy of the penis and the role of oncogenic HPV‐types has been also established in SCC of the penis. Prevention of SCC of the penis presupposes an identification of risk factors, early detection of all pre‐cancerous lesions and treatment of phimosis.

Basal cell carcinoma (BCC) is the most common skin cancer in humans, and although metastasis rarely occurs, the tumor cells are nevertheless able to invade and destroy the surrounding tissue. Intralesional injection of IFN-alpha has been found to be highly effective in inducing BCC regression by an unknown mechanism. We show that in untreated patients, BCC cells express CD95

Long-term ultraviolet light exposure of human skin epidermis in Caucasians is associated with an increased risk for the development of melanoma and nonmelanoma skin cancers. Ultraviolet radiation not only induces DNA damage in epidermal cells, it also interferes with skin homeostasis, which is maintained by a unique distribution pattern of apoptosis-inducing and apoptosis-preventing molecules. We demonstrate that, beside CD95 ligand, TRAIL and TRAIL receptors also function as important sensors in the human epidermis preserving skin integrity and preventing cell transformation. Ultraviolet irradiation extensively changes the expression pattern of some of these molecules, diminishing their sensor function. In particular, CD95 ligand and to a somewhat lesser extent TRAIL receptors are downregulated upon ultraviolet light exposure. CD95 ligand downregulation is not due to protein degradation as in situ hybridization experiments strongly support a transcriptional regulation. The downregulation of these molecules with sensor function increases the risk that aberrant cells are less efficiently eliminated. This concept is supported by the fact that the expression of these molecules is also low or absent in actinic keratosis, a precancerous state that has developed as the consequence of long-term ultraviolet exposure. Progression to invasive neoplasms is then accompanied by an upregulation of CD95 ligand and a downregulation of CD95 and of the TRAIL receptors. The high expression of CD95 ligand, TRAIL, and FLIP in squamous cell carcinoma may then contribute to the immune escape of the tumor, whereas the lack of expression of CD95 and TRAIL receptors prevents autolysis of the tumor.