<unk>  is an infection caused by the herpes simplex virus (HSV). The HSV is a double-stranded DNA virus categorised into two types; HSV-1 and HSV-2. HSV-1 is predominantly responsible for oral, facial and ocular infections whereas HSV-2 is responsible for most genital and cutaneous lower<unk>  lesions. Both HSV-1, and HSV-2 can be the cause of<unk> , although HSV-1 is the source of infection in around 90% of cases.<unk>  infections can present as acute or recurrent. Acute infection refers to the first invasion of the virus, and recurrent is when reactivation of the latent virus occurs. Acute<unk>  primarily occurs in children, particularly of those under the age of six years old. On external surfaces the virus is short lived, however it is extremely contagious. Most people acquire the virus via direct contact, it can enter the body by disrupting the integrity of skin, mucous membranes or enter via infected secretions such as saliva. The virus replicates once it has penetrated the epithelial cell, then it travels to the corresponding nerve ganglion (i.e. trigeminal ganglion) via sensory nerves endings. At the nerve ganglion the virus enters a latent phase and remains dormant until it is reactivated. Reactivation can be spontaneous or stimulated by a number of factors such as: reinfection by direct effect of stimuli, immunosuppression, ultraviolet light, febrile illnesses and stress. Risk factors Age: Primary<unk>  is common in children from 6 months to 5 years old. This virus is also common in young adults aged around 20–25. Immune system: The prevalence and severity of the disease is dependent on the host's immune response and the virulence of the virus. Environment: As this virus is very contagious it has the potential to spread quickly in enclosed environments e.g. 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.
Herpetic gingivostomatitis
Denture-related stomatitis
Tinea capitis
Actinic cheilitis
Angular cheilitis
Chancroid
Lentigo simplex
Contact stomatitis