COLD SORES - HERPES SIMPLEX INFECTION*
“Cold sores” are small, painful, fluid-filled blisters, usually on the lips, gums or roof of the mouth. They can be more widespread on the skin around the mouth, the face and even, in severe cases, extending onto the forehead. They are caused by a virus and are contagious.
They are also called oral herpes, and the cause is the herpes simplex virus. When the sores are present, there may be other symptoms such as fever and aching muscles.
They should be distinguished from “canker sores”. Canker sores only occur inside the mouth, on the tongue or soft palate (roof of the mouth), but not on the skin. They are not contagious, and are caused by substances that irritate the oral mucosa.
There are two types of herpes simplex virus (HSV), termed HSV-1 and HSV-2. These two viruses have distinctively different DNA, and both cause oral and genital lesions. HSV-1 is responsible for at least 80% of oral lesions, cold sores. HSV-2 causes the reverse, at least 80% of genital lesions. Oral/genital contact increases the likelihood of HSV-1 being the cause of genital herpes. This newsletter is about oral herpes, not genital herpes. The term “Cold Sore” will be used throughout.
Cold sores (oral herpes -HSV-1) infection (with or without noticeable infection) is common. In Western countries it is suggested, from surveys, that up to 65% of the population has detectable antibodies to HSV-1 by age 40 years.
Cause of Cold Sores
The cause of cold sores is the herpes simplex virus, type 1 (HSV-1) in at least 80% of cases. The remaining cases are due the herpes simplex virus, type 2 (HSV-2).
These viruses enter the body through small cuts or breaks in the skin, or oral mucous membrane or cracks in the lips. In the majority of cases, an uninfected person has direct contact with someone carrying the virus (either with or without noticeable lesions). Children can be exposed simply by touching an infected person. Adolescents and adults frequently get exposed by skin contact also, but may get their first exposure by kissing or sexual contact (especially for HSV-2).
Cold sores tend to be recurrent. Once infected, the virus continues to live and exist in the host cells after the sore has healed. It is then in a dormant state in nerve tissue. Certain conditions such as fever, stress (both emotional and physical), sunburn (ultraviolet light), fatigue, hormonal changes (eg menstruation), local trauma or dental work (especially with injections of local anaesthetic) can reactivate the virus, leading to another cold sore(s).
There are three stages after a person is infected with the herpes simplex viruses.
· Stage 1
Primary infection, when the virus enters the skin or mucous membrane, resulting in the “sore”. However, a sore or other symptoms may not develop, and you may not know you have the infection. This is referred to as asymptomatic infection.
· Stage 2
Latency, when the virus settles in the nerve tissue in the spine, the dorsal root ganglion, where it becomes inactive until reactivated by certain conditions as set out above.
· Stage 3
Recurrence, when the virus is reactivated.
The herpes simplex viruses multiply in human cells by utilising most of the human cells function; one of the HSV steps in multiplication is to take over the human cell’s nucleus and alter its structure. This altered nucleus (enlarged and lobulated) is one of the things used to make a diagnosis by microscopic examination. The reason sores appear is that, as they mature, the many HSV particles rupture the human cell’s membrane as they break out of the cell. Being nerve cells is the reason the sores are painful.
Signs and Symptoms of Cold Sores
After exposure there is an incubation period of 2 to 12 days, generally about 4 days.
There may be complete absence of signs or symptoms, asymptomatic infection.
In others, signs and symptoms of cold sores will last two to three weeks.
Initially there may be burning, or tingling, or even just itching at the infection site before the sores appear. Pain may also be present, but is generally most intense once the sores have appeared, even making eating and drinking difficult. With recurrent infections, these symptoms forewarn, and indicate the need for treatment.
Fever, tiredness, muscle aches and irritability may occur, as general symptoms.
Sometimes the lymph glands in the neck can swell and be painful.
Then the blisters erupt. These break down rapidly and appear as shallow grey ulcers, of varying size, on a reddish base. A few days later, they become scabbed-over. These are the oral sores.
Diagnosis of Cold Sores
A presumptive diagnosis can be made from the history, including the symptoms and signs as outlined above. The characteristic appearance of the herpes sores leaves little doubt about the diagnosis.
If a definitive diagnosis is required, various laboratory tests can be conducted:
· A sample, either tissue or fluid, from the sore(s) can be used to identify the virus as HSV.
· A virus culture.
· A microscopic examination of a tissue smear to show non-specific nucleus changes due to the HSV.
· Antigen and antibody studies (serological test to determine if the infection is caused by HSV-1 or HSV-2).
Treatment of Cold Sores
It is important to allow the sores to dry-out. Avoid using any type of cream or ointment, especially if such would keep the lesions moist.
Apply methylated spirits (undiluted) to the sores to help dry them. Apply every two hours.
Treat the fever if necessary.
When cold sores are treated by a General Practitioner, especially if severe and widespread, an antiviral agent such as acyclovir (Zovirax) will generally be prescribed.
Lysine is an essential amino acid. Taking an oral supplement of lysine can speed recovery time and reduce the chance of recurrent outbreaks. Full details of this important treatment and prophylaxis can be found in my June 2009 newsletter Lysine - Prevention and Treatment of Cold Sores & Other Conditions. Dosage for prevention: 500mg to 1000mg per day. Therapeutic dose: up to several grams a day, in divided doses.
Other treatments that have shown some benefit in the management of cold sores include vitamin C, zinc, vitamin E, flavonoids, Resveratrol and Astragalus.
It is important to avoid, as far as possible, factors that may bring about a recurrence (eg avoid excess exposure to sunlight) or to undertake treatment for a known cause (eg stress management).
Lysine, taken regularly as a preventive, can greatly reduce the frequency of recurrent outbreaks. After or during an event known to bring about a recurrence, the dose of lysine should be increased. Likewise, when there is a cold sore, the lysine dose should be at a therapeutic level, which will hasten recovery and reduce the severity of the lesion.
*Copyright 2011: The Huntly Centre.
Disclaimer: All material in the huntlycentre.com.au website is provided for informational or educational purposes only. Consult a health professional regarding the applicability of any opinions or recommendations expressed herein, with respect to your symptoms or medical condition.
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