There are many factors affecting erythema annulare, including infectious diseases, immune diseases and insect-borne diseases. Ringworm, Candida albicans, EBV, hepatitis C virus and genital herpes virus infections can cause erythema annulare; diseases such as prostate cancer, ovarian cancer, rectal cancer, liver cancer, rheumatic fever and systemic lupus erythematosus can also cause erythema annulare.