Dermatology is a branch of medicine dealing with the skin, its structure, functions, and diseases (from Greek derma, "skin"), as well as its appendages (nails, hair, sweat glands).
The skin is the largest organ of the body and certainly the most visible. Although many skin diseases are isolated, a significant portion of skin symptoms reflects a more generalised disease that affects other organs. Hence, a dermatologist is required to have a working knowledge of basic surgery, rheumatology (many rheumatic diseases can feature skin symptoms), neurology (the "neurocuteaneous syndromes", such as neurofibromatosis and tuberous sclerosis) and endocrinology.
Dermatology is often practiced in tandem with venereology, the specialism that diagnoses and treats sexually transmitted diseases, and phlebology, the specialism that deals with problems of the superficial venous system.
Dermatology has the benefit of having easy access to tissue for diagnosis. Culture or Gram staining of suspected infectious lesions may identify a pathogen and help direct therapy.
If the diagnosis is uncertain, or cutaneous malignancy is suspected, a small punch-hole biopsy can be taken under local anesthetic, to be examined by a specialist of histopathology. Antibiotic creams can help eliminate infections, while inflammatory skin diseases (such as eczema and psoriasis) often respond to steroid creams. Dermatologists relatively rarely have to resort to oral medications. These are reserved for diseases that cannot be treated with local applications. Antibiotics and immune suppressants are most often prescribed for dermatological problems.