herpes sim. virus

22 Jul

Herpes simplex viruses (types 1 and 2) is an infection that can affect the mouth, lips, eyes, genitals and skin. It is commonly seen presented in cold sores- small clusters of red, lesions that are found around the mouth. This infection can be spread from close contact (type 1) or sexual contact (type 2) and can also remain inactive for periods of time. Re-emergence in certain scenarios such as sunlight overexposure, immune suppression and stress.

- According to the WHO, herpes simplex virus type 1 affects 3.7 million people under 50 globally
- Type 2 herpes simplex virus impacts approx 491 million people between 15-49 years globally [1]
- About 20% of sexually active adults in the US carry herpes simplex virus type 2
- Found that women were more likely to get type 2 herpes simplex virus than men [2]
- Prevalence in adult general populations in sub-Saharan Africa ranges from 30% to 80% in women, and from 10% to 50% in men
- Herpes simplex virus type 2 is consistently higher in women and increases with age [3]
- Contact with infected person through:
- Kissing
- Touching eg. touching the face
- Sharing objects eg. sharing towels, cutlery etc
- Sexual intercourse
- Some infected people do not present with symptoms so they are known as ‘asymptomatic’ and when this infects someone else it is called ‘asymptomatic viral shedding’ [2]
Medical Students
- Two main human herpesviruses: HSV-1 and HSV-2
- HSV-related diseases include:
  - Cold sores
  - Genital herpes
  - Herpes stromal keratitis
  - Meningitis
  - Encephalitis
- The immune system is essential in controlling HSV but the virus has immune evasion mechanisms
- Immune response itself can contribute to pathogenesis (e.g. in stromal keratitis and encephalitis)
- Genetic polymorphisms affect individual susceptibility to severe HSV infections
- HSV has two replication phases:
  - Lytic cycle: virus invades host DNA, replicates, and produces new viral particles
  - Latent phase: virus lies dormant in neurons, reactivating later to cause disease
- Mechanisms of latency and reactivation remain incompletely understood
Patients
- Two common herpes viruses: HSV-1 (often causes cold sores) and HSV-2 (often causes genital herpes)
- HSV can also cause:
  - Stromal keratitis (eye infection that may cause vision loss)
  - Meningitis (swelling of brain lining)
  - Encephalitis (swelling of the brain itself)
- The body’s immune system helps control the virus, but HSV can sometimes hide from it
- In some cases, the immune system itself may cause damage, especially in the brain or eyes
- Some people are more likely to get severe infections because of their genetic differences
- HSV has two stages:
  - Lytic stage – virus is active and makes copies of itself inside the body’s cells
  - Latent stage – virus hides inside nerve cells and can wake up again later, causing symptoms [4]
- Contact with an infected person (sores or fluids)
- Unprotected sexual intercourse (eg. oral, anal or vaginal sex)
- Multiple sexual partners
- Being female
- History/ current infection of sexual nature or blood borne [5]
- Commonly presents with no/mild symptoms
- Painful ulcers found on the skin/ mouth
- Tingling/burning on the affected sites
- Vesicles/ sores found on the mouth
- Itchiness [6]
- Clinical assessment of presenting symptoms
- A swab can be taken from the sores and send for clinical evaluation at the lab
- Blood tests can be carried out to look for herpes IgG antibodies [2]
- Aphthous stomatitis- ulcers on the mouth that are painful and common
- Steven-Johnson syndrome- a rare condition caused by an extreme reaction to the immune system triggered by an infection/medicine
- Erythema multiforme- an allergic reaction to medicine/infection
- Herpangina- mouth blisters [7]
Medical Students
Mucocutaneous HSV Infection
- Isolated episodes may resolve without treatment
- First-line antivirals: acyclovir, valacyclovir, famciclovir (especially for primary infection)
- Acyclovir-resistant HSV (mainly in immunocompromised patients): treat with foscarnet
- Secondary bacterial infections:
  - Topical: mupirocin or neomycin-bacitracin
  - Systemic: penicillinase-resistant beta-lactams
- Systemic analgesics for pain relief
Gingivostomatitis and Pharyngitis
- Symptom relief with topical anaesthetics (dyclonine, benzocaine, viscous lidocaine)
- Severe cases treated with oral antivirals (acyclovir, valacyclovir, famciclovir)
Herpes Labialis
- Responds to oral or topical acyclovir
- Recurrent outbreak duration reduced with penciclovir, famciclovir, or valacyclovir
- Acyclovir-resistant strains are also resistant to penciclovir, famciclovir, and valacyclovir
- Docosanol may be effective
Herpetic Whitlow
- Typically resolves in 2 to 3 weeks without treatment
- Topical acyclovir is not proven effective
- Use oral or IV acyclovir in immunosuppressed or severe cases
Herpes Simplex Keratitis
- Treated with topical antivirals (e.g., trifluridine) under ophthalmologist supervision
Herpes Simplex CNS Infection
- Encephalitis: treated with acyclovir
- Viral meningitis: treated with IV acyclovir, generally well tolerated
Patients
Herpes simplex affecting the skin
- Single-time infections may heal on their own
- First treatments include acyclovir, valacyclovir, or famciclovir
- Resistant HSV in people with weak immune systems may need foscarnet
- Secondary infections:
  - Creams such as mupirocin or neomycin-bacitracin
  - Oral antibiotics for more severe infections
- Painkillers like ibuprofen or paracetamol can help
Infection of the mouth and throat (gingivostomatitis and pharyngitis)
- Use numbing creams or gels (e.g. benzocaine or lidocaine) for pain
- Antiviral tablets are needed in severe cases
Cold sores (herpes labialis)
- Treated with acyclovir cream or tablets
- Recurring flare-ups may be shortened with valacyclovir, penciclovir, or famciclovir
- Some virus strains are resistant to these treatments
- Docosanol cream may help if used frequently
Herpetic whitlow (finger infection)
- Usually heals in 2 to 3 weeks without any medicine
- Creams are usually not effective
- Tablets or IV medicine may be used in serious or immune-weak cases
Eye infection (herpes simplex keratitis)
- Treated with special eye drops under the care of an eye specialist
Brain or nerve infection (CNS herpes)
- Encephalitis: treated with acyclovir
- Meningitis: treated with IV acyclovir, usually works well [6]
- Oral herpes (affecting the mouth)
- Dehydration
- Herpetic whitlow- sores found on the hands/fingers
- Eczema herpitum- herpes flare up with people who have eczema
- Labial adhesions- complication of mouth herpes that limits mouth opening
- Eye diseases that can affect the cornea, retina and cause conjunctavitis
- Erythema multiforme- an allergic reaction to medicine/infection
- Pneumonia and oesophagitis from infections
- Rare:
  - Meningitis
  - Hepatitis [8]
- Herpes affecting the mouth is the same as herpes affecting the genital area
- People always show symptoms of herpes virus
- People are herpes are always infectious
- Herpes causes cervical cancer
- Herpes can be passed through the blood
- Herpes stops people having children
- You can give yourself herpes at another site if you already have it [9]
- How can I tell my partner(s) about the infection?
- Does my partner(s) need to get tested?
- How long does treatment take to be effective?
- How can I make herpes flare up less painful?
- How will I be managed if I am pregnant with herpes?
- British Association of Dermatologists
- Herpes Viruses Association
- New Zealand Herpes Foundation
[1] https://www.who.int/news-room/fact-sheets/detail/herpes-simplex-virus
[2] https://www.aad.org/public/diseases/a-z/herpes-simplex-causes
[3] https://pubmed.ncbi.nlm.nih.gov/15115627/#:~:text=Herpes simplex virus type 2 (HSV-2) is a,higher than in the USA]
[4]https://pubmed.ncbi.nlm.nih.gov/34676800/#:~:text=During%20lytic%20replication%20HSV%20produces,primary%20infection%20and%20upon%20reactivation.
[5] https://www.canada.ca/en/public-health/services/infectious-diseases/sexual-health-sexually-transmitted-infections/canadian-guidelines/herpes-simplex-virus/risk-factors-clinical-manifestation.html#a1
[6] https://www.msdmanuals.com/en-gb/professional/infectious-diseases/herpesviruses/herpes-simplex-virus-hsv-infections?query=cold%20sores
[7] https://www.ncbi.nlm.nih.gov/books/NBK482197/#:~:text=
[8] https://cks.nice.org.uk/topics/herpes-simplex-oral/background-information/complications/
[9] https://www.herpes.org.nz/about-herpes-questions/myths-and-facts-about-herpes#:~:text=Myth%3A