Cold sores (herpes labialis), also known as "lip fever" or "deaf fever", is an infectious disease mainly caused by the virus herpes simplex type 1 (HSV-1) belonging to the herpes virus family. It can also be caused, albeit to a lesser extent, by the virus herpes simplex type 2 (HSV-2) which usually causes genital herpes. Infection with the herpes simplex virus type 1 occurs through saliva, kisses or, in general, through direct contact with infected people. The virus enters the body through the skin and mucous membranes, where it infects epithelial cells and causes their death. This results in the formation of small blisters, lesions and whitish, or reddish, serum-filled blisters and blisters located predominantly on the lips. Sometimes, cold sores can also occur on the cheeks, nose and palate.
After the appearance of the lesions, the repair process begins, which usually lasts 7/10 days, with the formation of scabs.
Once penetrated into the organism, the virus lurks in specialized structures of the nervous system (the local neuronal ganglia) where it can remain inactive even for long periods. lead to another infection (relapse).
Herpetic infections, in fact, are known for their ability to recur periodically. They are widespread and the World Health Organization has estimated that cold sores are a problem that affects 3.7 billion people in the world under the age of 50 (data relating to the year 2012).Symptoms
Symptoms of cold sores include:
- red blisters, filled with clear liquid
- pain and burning in areas where vesicles are present
- itch and momentary loss of sensitivity to touch
The blisters can burst, exposing the skin to the risk of further infection. A few days after their appearance, small moist crusts may form which then become dry. The scabs come off causing the skin to bleed until the skin tissue is renewed.
More specifically, the infection with the herpes simplex virus type 1 (HSV-1) goes through several stages, which are accompanied by specific disorders (symptoms):
- prodromal phase (which precedes the appearance of the disorders), the virus begins to replicate in the skin, most commonly on the lip, giving a localized sensation of tension, tingling and throbbing. With the passage of time, generally from a few hours to 48 hours, it is possible to feel a sense of tingling (also called "pinpricks" on the lips) or burning, sometimes of pain. Then a small swollen, hard and painful spot appears on the skin
- inflammatory phase, on the area of the lips affected by herpes, tiny red spots appear which gradually enlarge and fill with a translucent yellow liquid to form small vesicles arranged in clusters along the outer edge of the lips. These bubbles can reach sizes ranging from 2 to 5 mm During this phase, which can last from 2 to 3 days, the peak of herpes contagiousness increases considerably. Cold sores can also occur around the nose, on the cheeks or on the roof of the mouth
- ulcerative stage, the blisters tend to burst, uncovering the underlying skin and releasing the (extremely infectious) fluid inside them. Pain appears. The breaking of the bubbles gives rise to a "single large red lesion which often complicates certain daily activities such as drinking or brushing the teeth.
- crust formation, over the uncovered ulcer a thin film forms which then hardens to form a crust. Under this protection the skin begins to reform. The presence of the crust, however, causes considerable discomfort such as severe itching and dryness and, not being elastic, it tends to break when talking or smiling, causing small bleeding wounds and making it itchy. This stage is usually the longest, and least contagious, ranging from 3 to 4 days. the crust falls off and the underlying skin appears repaired
Furthermore, in the phase following the onset of herpes, some people experience ailments similar to those of the flu (flu-like syndrome) such as:
- painful gums
- muscle aches
- burning throat
- general malaise
- swollen lymph nodes
However, the signs and disorders vary depending on whether it is the first episode or a relapse. Relapses usually appear in the same spot each time and tend to be less severe than in the first outbreak.Causes
Cold sores are caused by infection with the virus Herpes simplex type 1 (HSV-1) or, more rarely, type 2 (HSV-2), both of which belong to the herpes virus family. The virus infects only humans and is transmitted from person to person through contact. The first infection generally occurs during childhood and can occur even in the absence of disorders (asymptomatic). It determines a reaction of the body's defense system which, however, does not eliminate the virus that remains in the body for life. Having an affinity for nerve tissue, the virus reaches the nerve endings present at the point where the contact took place and the local nerve ganglia. Here it remains inactive (latent phase), in perfect balance with the body's immune defenses, until stimuli of a different nature, such as fever, emotional and physical stress, menstruation, surgery, infections, immunosuppressive therapies, exposure to ultraviolet rays and / or in the cold, by altering the immune defenses, they create favorable conditions for the reproduction of the virus and its migration from the neuronal ganglion to the skin through the nervous pathway, causing relapse.Diagnosis
To ascertain (diagnose) cold sores, it is usually sufficient for the doctor to observe the diseased part, carefully examining the site and distribution of the lesions, and inquire about the possible presence of disorders (symptoms) that appeared before the skin lesions : sensation of heat, pain and itching (prodromal symptoms). In the most difficult cases it may be necessary to use laboratory tests. The certainty that it is an infection with herpes simplex type 1however, it can only be given by the finding of the virus in the biological material taken from the lesions.Therapy
There are no medicines that allow you to completely eradicate l "herpes simplex type 1 from the body. The treatment of cold sores involves the use of specific antiviral drugs (mainly Aciclovir), generally for local use in the form of creams. However, these do not greatly change the course of the disease. Local applications of creams containing Aciclovir or its derivatives have in fact a modest effectiveness in reducing lesions, but they reduce the sensation of pain and burning and should be used in mild cases of infection to decrease discomfort or to reduce the risk of contagion. All local applications are effective only if you start in the prodromal phase, ie in the first 48 hours. To remove the symptom of itching and burning and prevent other infections from occurring on skin lesions, aluminum chloride gel (called astringent gel) can be used to be applied several times a day.
To prevent herpes from appearing again, it is good to avoid exposing yourself to those triggers that everyone has experienced in the past: among them there may be smoking, stress, poor sleep and prolonged sun exposure or without adequate protection.
More severe forms of cold sores may require antiviral drug treatment to be taken by mouth (oral) or intravenous injection (intravenous infusion), under medical supervision. Oral antivirals such as Aciclovir or Valaciclovir are effective in the treatment of herpes and can be used, in severe cases, for 5 - 7 days; the physician's decision to prescribe oral antiviral treatment is based on the intensity and location of the manifestations and the frequency of relapses.Prevention
The prevention of viral infections is carried out by observing the main hygiene rules. To avoid spreading cold sores to other people or other parts of your body, simple precautions are necessary:
- avoid contact with the skin of infected people while vesicles are present. The virus spreads more easily when there are moist secretions from the blisters and lesions
- avoid sharing utensils, towels, cutlery and other objects that can spread the virus when vesicles are present
- keep your hands clean, wash your hands often and thoroughly before touching yourself and other people, especially children
In some people, the virus that causes cold sores can cause problems in other parts of the body, including:
- fingers, both herpes simplex type 1 (HSV-1) and type 2 (HSV-2) can spread to the fingers. This type of infection is often referred to as herpetic patereccio. It is seen in children with cold sores who have a habit of thumb sucking or in health care workers exposed to mouth secretions. In adults, the lesion can also occur following contact with HSV-2 infected genitals
- eyes, herpes simplex type 1 can sometimes cause eye infections which, if repeated, can leave scars and lesions, resulting in vision problems or blindness
- diffuse areas of skin, people who have eczema are at a higher risk of having a cold sore all over the body (eczema herpetic)
- other organs, in people with weakened immune systems, the virus can also affect organs such as the spinal cord and brain, causing encephalitis
Diseases, conditions, and treatments that increase the risk of complications include:
- HIV / AIDS infection
- severe burns
- cancer chemotherapy
- anti-rejection drugs for organ transplants
Saleh D, Bermudez R. Herpes, Simplex, Type 1. StatPearls [Internet]. 2018; Feb 13
Looker KJ, Magaret AS, May MT, Turner KME, Vickerman P, Gottlieb SL, Newman LM. Global and Regional Estimates of Prevalent and Incident Herpes Simplex Virus Type 1 Infections in 2012. Plos One. 2015; 10In-depth link
Humanitas Research Hospital. Herpes simplex
NHS. Cold sores (English)