The Collaborative International Dictionary of English v.0.48:

Herpes \Her"pes\, n. [L., fr. Gr. "e`rphs, fr. "e`rpein to
   creep.] (Med.)
   An eruption of the skin, taking various names, according to
   its form, or the part affected, caused by a herpesvirus
   infection; especially, an eruption of vesicles in small
   distinct clusters, accompanied with itching or tingling,
   including shingles, ringworm, and the like; -- so called from
   its tendency to creep or spread from one part of the skin to
   another.
   [1913 Webster +PJC]

WordNet (r) 3.0 (2006):

herpes
    n 1: viral diseases causing eruptions of the skin or mucous
         membrane
    2: any of the animal viruses that cause painful blisters on the
       skin [syn: herpes, herpes virus]

Moby Thesaurus II by Grady Ward, 1.0:

153 Moby Thesaurus words for "herpes":
   African lethargy, Asiatic cholera, Chagres fever, German measles,
   Haverhill fever, acne, acne vulgaris, acute articular rheumatism,
   ague, alkali disease, amebiasis, amebic dysentery, anthrax,
   bacillary dysentery, bastard measles, black death, black fever,
   blackwater fever, breakbone fever, brucellosis, bubonic plague,
   cachectic fever, cerebral rheumatism, chicken pox, cholera, cowpox,
   dandy fever, deer fly fever, dengue, dengue fever, dermamycosis,
   dermatitis, dermatosis, diphtheria, dumdum fever, dysentery,
   eczema, elephantiasis, encephalitis lethargica, enteric fever,
   epithelioma, erysipelas, erythema, exanthem, famine fever,
   five-day fever, flu, frambesia, glandular fever, grippe,
   hansenosis, heat rash, hepatitis, herpes simplex, herpes zoster,
   histoplasmosis, hives, hookworm, hydrophobia, impetigo,
   infantile paralysis, infectious mononucleosis,
   inflammatory rheumatism, influenza, itch, jail fever, jungle rot,
   kala azar, kissing disease, lepra, leprosy, leptospirosis, lichen,
   lichen primus, loa loa, loaiasis, lockjaw, lupus, lupus vulgaris,
   madness, malaria, malarial fever, marsh fever, measles, meningitis,
   miliaria, milzbrand, mumps, ornithosis, osteomyelitis,
   paratyphoid fever, parotitis, parrot fever, pemphigus, pertussis,
   pneumonia, polio, poliomyelitis, polyarthritis rheumatism, ponos,
   prickly heat, pruigo, pruritus, psittacosis, psora, rabbit fever,
   rabies, rat-bite fever, relapsing fever, rheumatic fever,
   rickettsialpox, ringworm, rubella, rubeola, scabies, scarlatina,
   scarlet fever, schistosomiasis, septic sore throat, shingles,
   skin cancer, sleeping sickness, sleepy sickness, smallpox,
   snail fever, splenic fever, spotted fever, strep throat,
   swamp fever, tetanus, tetter, thrush, tinea, trench fever,
   trench mouth, tuberculosis, tularemia, typhoid, typhoid fever,
   typhus, typhus fever, undulant fever, vaccinia, varicella, variola,
   venereal disease, viral dysentery, whooping cough, yaws,
   yellow fever, yellow jack, zona, zoster