Oral lesions of opportunistic infections and neoplasms are associated with immunosuppression caused by the human immunodeficiency virus (HIV). These include oral candidiasis, viral lesions such as warts, herpes simplex, herpes zoster and hairy leukoplakia, as well as Kaposi's sarcoma and an aggressive form of periodontal disease. Many of these can occur as the first clinical signs of HIV infection. Thus, careful oral examination is an important part of the clinical evaluation.