nurseries and orphanages.Epidemiology: Those living in developing countries are at a higher risk of HSV-1 infection. It has been reported that around a 1/3rd of children living in developing countries are HSV-1 positive by 5 years old and 70-80% of the population are infected by the age of adolescence. In developed countries only 20% of children are infected at the age of 5 and there is no significant increase in disease prevalence until 20–40 years old where the percentage of infected individuals ranges from 40-60% Socio-economic status: Those with a lower income have a higher risk of HSV-1 infection at a younger age.Race: Studies have demonstrated that in the USA 35% of African Americans by the age of 5 have presented with the disease whereas only 18% of White Americans are affected. Pathophysiology
Herpetic gingivostomatitis originates from a primary infection of HSV-1. The series of events that take place during this infection include replication of the herpes simplex virus, cell lysis and finally, destruction of the mucosal tissue.HSV-1 can very easily enter and replicate within epidermal and dermal cells through skin or mucosal surfaces which have abrasions. This results in numerous small vesicles or blisters of up to 1-2mm on the oral mucosa, erosions on the lips, eventual hemorrhagic crusting and even ulceration, covered by a yellowish-grey pseudomembrane, surrounded by an erythematous halo.As the virus continues to replicate and incolulate in great amounts, it can enter autonomic or sensory ganglia, where it travels within axons to reach ganglionic nerve bodies.
One way to distinguish between the herpes virus (and hence herpetic gingivostomatitis) and varicella virus is by direct immunohistochemistry using fluorescent antibodies. Differential diagnosis
Diagnosis of HG is very much clinically based. Therefore, it is imperative to rule out other diseases that present similarly, bearing in mind the past medical history of the patient. Some differential diagnoses to bear in mind when considering herpetic gingivostomatitis are:

Teething in infants:  A study mentioned that  "primary  tooth  eruption begins  at  about the  time that  infants  are  losing  maternal antibody protection  against  the  herpes  virus. Also, reports  on  teething  difficulties  have  recorded  symptoms  which  are  remarkably  consistent  with  primary oral  herpetic  infection  such as  fever,  irritability,  sleeplessness,  and difficulty  with eating." Another study highlighted that "younger infants  with  higher residual  levels  of  antibodies  would experience  milder infections  and  these  would be  more likely  to  go unrecognized  or  be  dismissed  as  teething  difficulty." Herpangina: It is a disease that is caused by the Coxackie A virus rather than a herpes virus. In herpangina, ulcers are usually isolated to the soft palate and anterior pillar of the mouth.