It should not be confused with conditions caused by other viruses in the herpesviridae family such as herpes zoster, which is caused by varicella zoster virus. The differential diagnosis includes hand, foot and mouth disease due to similar lesions on the skin. Lymphangioma circumscriptum and dermatitis herpetiformis may also have a similar appearance.
Herpes of the mouth is a viral infection. The virus HSV-1 may be transmitted by droplet spread – direct contact with saliva or even respiratory droplets. These droplets must make contact with broken skin or the mucous membranes in order to infect a person. The method of spread can involve kissing an infected person or even through touch. It can also be spread through the use of contaminated kitchen utensils. Sexual contact accounts for a small number of cases of HSV-1. Nevertheless it is a consideration when genital lesions are present. HSV-2 on the other hand is usually transmitted through sexual contact.
A 2004 study in the New England Journal of Medicine found that suppressive therapy decreases the risk of HSV-2 transmission from symptomatic, infected partners to uninfected partners by 48%. So “the risk of transmission is significantly reduced, but cannot be eliminated even with suppressive therapy,” Johnston explains, and she stresses that the virus can be passed along even without signs or symptoms.