AIDS patient with drug allergy. Lesion on a patient's torso due to a reaction to the anti- bacterial drug co-trimoxazole. This condition is also known as a fixed drug eruption and always affects the same area of the body, although repeated use of the drug leads to more severe symptoms. AIDS (acquired immune deficiency syndrome) is a disease caused by the human immunodeficiency virus (HIV). It causes weakening of the immune system, making the patient susceptible to opportunistic infections and making normally harmless infections life threatening. In Africa lack of access to a wide variety of drugs makes AIDS a major public health concern.