The original use was against normally fatal or debilitating illness such as adult encephalitis, keratitis, in immunocompromised (transplant) patients, or disseminated herpes zoster.
Herpes is a broad category -- it includes the virus that causes chickenpox and shingles (varicella zoster) as well as the germs responsible for glandular fever and Kaposi's sarcoma.
Facial sweating during salivation has also been described in diabetes mellitus, cluster headache, following chorda tympani injury, and following facial herpes zoster.
