A dermatologist diagnoses the causes of skin lesions and implements appropriate treatment.Dermatology is the branch of medicine dealing with skin diseases. Related medical disciplines to dermatology include cosmetology and venereology .A dermatologist is a specialist in dermatology, i.e. the branch of medicine dealing with the functioning of the skin and its diseases (including diseases of the hair and nails). The dermatologist examines the skin and looks for possible causes of abnormalities in its appearance. It is worth remembering that disturbing changes do not necessarily have to originate from a malfunction of the skin itself, but are often a consequence of internal diseases, e.g. hormonal changes, tumours, infectious diseases, allergies, as well as venereal diseases.