AIDS man with candidiasis. Man's foot showing scaly plaques due to candidiasis. Candidiasis is a skin infection caused by a fungus (Candida sp.). It can be easily treated with an anti-fungal agent. 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, where this patient is from, lack of access to drugs and information makes AIDS a major public health concern.