What is Herpes Simplex Type 1?
The Herpes simplex virus type 1 (HSV-1) is part of the Alphaherpesviridae family. This virus has a complex structure, including a DNA core, a protective coat called a capsid, and a spiky envelope. The way HSV-1 works involves first infecting skin cells, then lying dormant, mainly in nerve cells, before becoming active again. HSV-1 is known to cause initial and recurring painful sores, typically around the mouth or genital area.
The symptoms of HSV-1 can vary, including sores around the mouth, an infection of the hair follicles (called herpetic sycosis), a condition spread among wrestlers (known as herpes gladiatorum), infections on fingers (herpetic whitlow), eye infections, brain inflammation (herpes encephalitis), a rash caused by HSV on areas of the skin with eczema (known as Kaposi varicelliform eruption), and severe or long-lasting HSV infections. Treatments with antiviral medication can help control the progress of HSV infection.
What Causes Herpes Simplex Type 1?
The chances of getting HSV-1, a type of herpes virus, depends on the type of infection. So, the risk factors vary. For instance, if we talk about oral herpes, the risk factors could include any activity that brings one in contact with an infected person’s saliva. So, if you share drinks or cosmetics, or if you are involved in mouth-to-mouth contact with an infected person, it increases your risk.
If it’s a specific kind of herpes virus infection that affects the beard area (known as herpetic sycosis), you are at risk if you shave closely with a razor blade when there’s an active oral herpes infection.
There’s a type of herpes infection primarily seen in athletes engaged in high-contact sports like rugby, wrestling, MMA, and boxing, known as herpes gladiatorum. Here, participation in such sports is the risk factor.
Children who suck their thumbs or bite their nails, and adults who are in the medical or dental professions are at risk of herpetic whitlow, another type of herpes virus infection that affects the fingers. Although, it’s more commonly caused by HSV-2 virus in adults.
If someone has changes (mutations) in certain genes like TRL-3 or UNC-93B, they are at a higher risk of getting herpes encephalitis, which is a serious brain infection.
For eczema herpeticum, another herpes virus infection that affects skin especially in people suffering from skin conditions, poor skin barrier function increases the risk. Conditions like atopic dermatitis, Darier disease, Hailey-Hailey disease, mycosis fungoides, and all variants of ichthyosis could contribute to this. The risk also increases if you use certain medications like topical calcineurin inhibitors.
Lastly, people with weakened immunity are at an increased risk of getting severe or continued HSV infection. This could include those who received transplants (like solid organ or stem cell), HIV infected people, or patients with leukemia or lymphoma.
Risk Factors and Frequency for Herpes Simplex Type 1
Around one-third of people worldwide have had symptoms of HSV-1, a type of herpes virus, at least once in their lives. This virus first infects people who don’t already have antibodies against either HSV-1 or HSV-2. People who already have antibodies against one type of HSV can still get infected with the other type. Sometimes, the virus reactivates, leading to another infection. Usually, these reactivations don’t cause symptoms, but the virus can still be spread.
About 1 in 1000 newborns in the United States gets infected with the herpes simplex virus, typically during vaginal birth. Women who have recurring genital herpes generally have a low chance of passing the virus to their babies during birth. However, if a woman gets genital herpes for the first time while she’s pregnant, her chance of passing the virus to her baby is higher.
- It’s important to know that a type of brain infection called herpes encephalitis, caused by the herpes virus, is the most common deadly brain infection in the United States.
- Also, infection with the herpes virus in the eye is a major cause of blindness in the United States.
Signs and Symptoms of Herpes Simplex Type 1
HSV-1, or the Herpes Simplex Virus, often shows no symptoms at all. However, when symptoms do appear, they can take a lot of different forms, which include cold sores, infections in hair follicles, infections spread across the skin, and more.
A common symptom of HSV-1 is cold sores on or around the mouth and lips. These usually show up a few days to a week after exposure to the virus. The person may feel generally unwell or feverish, and may experience localized discomfort before the sores appear. They initially look like small, painful blisters, and they may turn into ulcers before healing over the course of two to six weeks. If the cold sores come back, they often develop around the edges of the lips, and the symptoms aren’t as severe.
There are many other ways HSV-1 can present itself. It can cause an infection in the hair follicles which usually appears in the beard area after shaving. This condition is known as herpetic sycosis and usually heals by itself in two to three weeks. HSV-1 can also cause persistent infections in people with immunity issues, leading to large sores or pustules that grow quickly, and these individuals can also have respiratory or digestive symptoms.
- Herpes gladiatorum shows up as lesions on the neck, face, or forearms within a few days after exposure and is common in athletes.
- Herpetic whitlow develops as deep blisters on the fingers or around the nails along with potential swelling of nearby lymph nodes.
- Ocular HSV is an infection of the eyes causing swelling, tearing, and sensitivity to light. This infection can recur and is a leading cause of blindness in the U.S. if it leads to corneal ulcers.
- Herpes encephalitis is a serious brain infection, potentially fatal, caused by HSV-1. Patients may have a fever and altered mental status.
- Kaposi varicelliform eruption, or eczema herpeticum is a widespread HSV infection in cases of compromised skin barriers and is characterized by small, crusted-over sores.
- Neonatal herpes appears in infants between the fifth and fourteenth day of life, primarily affecting the scalp and torso and potentially involving the central nervous system.
Testing for Herpes Simplex Type 1
The best method for diagnosing an HSV-1 infection, also known as oral herpes, is through a process called serology. Serology involves detecting antibodies in a patient’s blood using a procedure called a Western Blot. The most sensitive and precise mechanism is a test known as a viral polymerase chain reaction (PCR). However, antibody detection via serology is still regarded as the superior method.
The virus can also be diagnosed using alternative methods such as a viral culture, a direct fluorescent antibody (DFA) assay, or a Tzanck smear test. It is worth noting that while a Tzanck smear can detect the infection, it can’t distinguish between HSV and another virus called Varicella-Zoster Virus (VZV) because it identifies multinucleated giant cells that are present in both. On the other hand, the DFA assay is capable of differentiating between the two viruses.
Treatment Options for Herpes Simplex Type 1
The current advice for treating oral and lip herpes, also known as orolabial herpes, is to take oral valacyclovir. This involves taking 2 grams of the medication twice in one day. If you tend to get herpes outbreaks often, it might be a good idea to take medication regularly as a preventative measure. If you have under ten outbreaks a year, a daily dose of 500 mg of valacyclovir is recommended. But, if you have more than ten outbreaks annually, then you should be taking 1 gram of valacyclovir every day.
If you’re dealing with eczema herpeticum, a skin infection, the typical treatment lasts for 10 to 14 days. You can use acyclovir, a medication dosed at 15 mg/kg with a maximum of 400mg, and you’ll need to take it 3 to 5 times every day. Alternatively, you can also take Valacyclovir, with doses of 1 gram twice a day.
For those with severe, chronic Herpes Simplex Virus (HSV) who also have weakened immune systems, the aim of treatment is to continually suppress the virus. For these patients, the recommendation is for a daily dose of 400 to 800 mg of acyclovir, taken 2 to 3 times, or 500 mg of valacyclovir, taken twice.
What else can Herpes Simplex Type 1 be?
When a doctor is trying to diagnose a lips or mouth infection caused by the HSV-1 (Herpes Simplex Virus), they might consider other conditions that have similar symptoms. These include:
- Aphthous stomatitis (mouth ulcers)
- Stevens-Johnson syndrome (a severe skin issue)
- Erythema multiforme major (a skin disorder resulting from an allergic reaction or infection)
- Herpangina (a viral illness causing blisters and ulcers in the mouth)
They can differentiate between these different conditions based on the person’s medical history and the results of a physical examination.
In addition, when diagnosing herpetic whitlow (a finger infection caused by the herpes virus), doctors also would think about other conditions that can cause similar symptoms. These include:
- Blistering dactylitis (a bacterial infection of the fingers)
- Acute or chronic paronychia (an infection of the skin around the nails)
What to expect with Herpes Simplex Type 1
In general, most HSV-1 (a type of herpes virus) infections do not cause symptoms. If symptoms do occur, they usually result in mild, recurring skin lesions. The potential effects of an HSV-1 infection can differ greatly, based on where the virus manifests in the body. Generally, HSV-1 infections often follow a long-term pattern of lying dormant and then reactivating.
HSV encephalitis, which is a type of brain inflammation caused by the virus, has very serious consequences and can lead to death in about 70% of cases if not treated. The prognosis can be quite serious for ocular HSV (eye infection) too, particularly if the patient develops a ruptured eyeball or corneal scarring, since these conditions can eventually cause blindness.
