Erythema multiforme presenting as chronic oral ulceration due to unrecognised herpes simplex virus infection

Chronic mucocutaneous herpes simplex virus and varicella zoster virus infections

Chronic herpes simplex virus (CHSV) and chronic varicella zoster virus (CVZV) are defined as atypical mucocutaneous wart-like and/or ulcerative HSV or VZV infections, persisting for at least 1 month. Both are commonly associated with HIV infection and may occasionally present with other types of immunosuppression. CHSV and CVZV occur despite the immune restoration effect of highly active antiretroviral therapy for HIV. The clinical polymorphism of CHSV and CVZV makes recognition difficult. Histology, immunohistology, PCR and viral culture all help to confirm the diagnosis. Treatment is frequently complicated by resistance to thymidine kinase (TK)-dependent antivirals, including acyclovir, valacyclovir and famciclovir. Viral culture remains an essential tool for antiviral drug susceptibility testing. Therapeutic alternatives include non-TK-dependent antivirals, such as foscarnet or cidofovir, which directly target viral DNA polymerase. With few exceptions, CHSV and CVZV infections do not constitute significant risk factors for disseminated cutaneous or systemic infection. This review compares the similarities of and differences between CHSV and CVZV infections.