AIDS: All physical examinations of HIV-infected individuals should include a detailed examination of the mouth, since oral lesions are common. There are about 40 oral manifestations of HIV infections that may be the first clinical features of the disease. HIV-related cancers, such as Kaposi's sarcoma or lymphoma, may present as oral lesions. A variety of bacterial infections may be found in the mouth, including linear gingival erythema, necrotizing ulcerative periodontitis, tuberculosis, Mycobacterium avium complex, and bacillary angiomatosis. Viral infections include herpes infections, cytomegalovirus ulcers, hairy leukoplakia, and warts. Among fungal infections, various types of candidiasis are common, and histoplasmosis or cryptococcosis may also cause lesions. Other manifestations include recurrent aphthous ulcers, immune thrombocytopenic purpura, HIV-salivary gland disease, and pigmentation disorders. Treatments are available for many of these disorders.