Most of the time when herpes simplex virus or HSV infects a person there are no symptoms, in fact it also usually moves from one person to another in the absence of symptoms so therefore it can move through a population silently once in a while though it can cause symptoms and typically those are in the form of skin and mucous membrane lesions which could be divided into infections above the waist mostly involving the mouth in the tongue and those below the waist involving the genitals. There are two types of herpes simplex virus which is hsv-1 and hsv-2, both of which are part of a larger family of enveloped double stranded DNA viruses, the herpes virus hsv-1 tends to cause infections above the waist and hsv-2 tends to cause infections below the waist but there’s a lot of crossover because both viruses can cause both types of infections. Although herpes is most contagious when there are virus filth lesions present, It could also spread by asymptomatic shedding which means that herpes viruses can be in the saliva or genital secretions even when there are no signs of a cold sore or genital lesion. Typically when herpes virus lands on a new host, in other words a person who’s never had herpes before, it dives into small cracks in the skin or mucosa and binds to epithelial cell receptors which triggers those cells to internalize a virus once inside the virus starts at the lytic cycle which is where its DNA gets transcribed and translated by cellular enzymes which help to form viral proteins which are packaged into new herpes. Viruses which can leave to go off and infect neighboring epithelial cells. Hsv-1 and hsv-2 also infect nearby sensory neurons and travel up their axon to the neuron cell body to start up the latent cycle, the sensory neurons of the face have their cell bodies in the trigeminal ganglia and those are on the genitalia are located in the sacral ganglia so that’s ultimately where the herpes virus settles in for life, you see those sensory neurons aren’t destroyed instead they become a permanent home for the herpes virus and from time to time the herpes virus makes a few viral copies of itself and sends those virus particles back down the axon so they can get released and infect epithelial cells since the trigeminal and sacral ganglia serve just one side of the face or body herpes vesicles and ulcers develop on the ipsilateral or same side as the affected ganglia. This can happen over and over again throughout a person’s lifetime with classic triggers being things like stress, skin damage and viral illnesses. Recurrent episodes are usually less severe than the primary infection and sometimes there are no symptoms at all and when there are symptoms, there might be characteristic tingling or burning sensation called a prodrome. One or two days before the blisters appear in oral and genital herpes, the primary infection is most often asymptomatic having said that in oral herpes when it does cause symptoms, it usually affects children and it causes lesions on the palate, gums, tongue, lip and facial area as well as a fever and enlarged lymph nodes, the lesions themselves are typically clusters of small painful fluid-filled blisters that ooze in ulcerate and then eventually heal after a few weeks.
In older children and adults, a common symptom is pharyngitis, most of the time like primary infection reactivation doesn’t cause any symptoms but when it does, the most common pattern is having a handful of blisters at the Vermilion border, the border of the lip on one side of the face, these blisters are smaller and typically heal over a week’s time, primary infection can cause symptoms like ulcers and pustules which form on the labia majora, labia minora, mons pubis vaginal mucosa and cervix in women and on the shaft of the penis in men like oral herpes most of the time, reactivation doesn’t cause any symptoms but when it does the most common pattern is to have a few blisters that resolve rapidly in about a week in addition to oral and genital infections, HSV can also affect other areas. When it affects the finger tip or nail bed, it’s called herpetic Whitlow and this might happen if the finger rubs up against an active lesion around the mouth or genital area, once it affects the finger tip, it’s also easy for it to get carried over to other areas in the body to spread the infection.