Improving the management of seborrhoeic dermatitis.

Seborrhoeic dermatitis usually starts at puberty with a peak incidence at 40 years of age and is more common in males. Patients develop symmetrical, well demarcated, dull or yellowish red patches and plaques with overlying adherent, yellowish greasy scales. Seborrhoeic dermatitis has a distinctive distribution in areas rich in sebaceous glands - the scalp, eyebrows, glabella, nasolabial and nasofacial folds, cheeks, peri-auricular skin, pre-sternal and interscapular areas. It may occur in flexures, especially the axillae, groin, anogenital skin, infra-mammary skin and the umbilicus. Some patients may develop blepharitis with erythematous eyelids and destruction of eyelash follicles. Patients with HIV infection, neurological diseases, including parkinsonism and cranial nerve palsies, have a higher incidence of seborrhoeic dermatitis. Patients presenting with sudden onset severe seborrhoeic dermatitis should be screened for risk factors for HIV. Patients should be referred in the following situations: diagnostic uncertainty - consider other differential diagnoses; failure to respond to first-line treatment after four weeks - consider secondary changes e.g. bacterial infection, flexural intertrigo, lichenification, otitis externa; and severe/widespread disease. Patients with seborrhoeic dermatitis have a good prognosis, particularly infantile seborrhoeic dermatitis, which usually remits within a few weeks or months and does not recur.

The importance of a full clinical examination: assessment of index lesions referred to a skin cancer clinic without a total body skin examination would miss one in three melanomas.

Traditional clinical teaching emphasises the importance of a full clinical examination. In the clinical assessment of lesions that may be skin cancer, full examination allows detection of incidental lesions, as well as helping in the characterisation of the index lesion. Despite this, a total body skin examination is not always performed. Based on two prospective studies of over 1,800 sequential patients in two UK centres we show that over one third of melanomas detected in secondary care are found as incidental lesions, in patients referred for assessment of other potential skin cancers. The majority of these melanomas occurred in patients whose index lesion turned out to be benign. Alternative models of care--for instance some models of teledermatology in which a total body skin examination is not performed by a competent practitioner--cannot be considered equivalent to a traditional consultation and, if adopted uncritically, without system change, will likely lead to melanomas being missed.