Dermatology is the branch of medicine dealing with the skin, nails, hair and its diseases. It is a specialty with both medical and surgical aspects. A dermatologist treats diseases, in the widest sense, and some cosmetic problems of the skin, scalp, hair, and nails.

Venereology is a branch of medicine that is concerned with the study and treatment of sexually transmitted diseases. A physician specializing in venereology is called a venereologist. The specialty is usually combined with dermatology. The venereal diseases include bacterial, viral, fungal, and parasitic infections.

Leprosy is an infectious disease affecting the skin and nerves which, if left untreated, can lead to disability and blindness. It is caused by bacteria called Myobacterium leprae, these bacteria multiply slowly meaning the incubation period can be quite long, often around five years but in some cases symptoms can take up to 20 years to appear.