There are literally thousands of skin diseases. A large part of a dermatologist's role is the diagnosis of rashes, lumps, spots, and skin blemishes of all descriptions (and also abnormalities of hair and nails). Once a diagnosis is made, then advice can be given about the nature and prognosis of the condition, and the kinds of treatment that are available.

Information on conditions such as acne, psoriasis, eczema, keratosis pilaris, lichen planus, folliculitis, scabies, pemphigoid, alopecia areata, fungal infections, tinea versicolor (to name just a very few) are available on numerous internet sites. The New Zealand Dermatological Society website http://www.dermnet.org.nz is an excellent source of information, as is the emedicine site http://www.emedicine.com/specialties.htm.