herpes sim. virus

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.

Epidemiology

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]

Source: DermNetNZ.org

Herpes Simplex Virus
Yellow sore found on the mouth

Source: DermNetNZ.org

Herpes Simplex Virus
Sores present on top and bottom lips with redness

Pathophysiology [4]

Medical Student
- The two prevalent human viruses are HSV-1 and HSV-2.

Diseases caused by the viruses include cold sores, genital herpes, herpes stromal keratitis, meningitis, and encephalitis.
Immune responses are crucial in controlling HSV, but the virus can evade them.
Immune response can contribute to pathogenesis, as seen in stromal keratitis and encephalitis.
Genetic polymorphisms in humans can explain different susceptibilities to severe HSV disease.
HSV has two replication cycles: lytic and latent.
- Latency occurs in neurons and can lead to disease during primary infection or reactivation. This topic is not fully understood in terms of function and mechanisms to cause infection.
- Lytic cycles occurs when the virus introduces its genome into a host cell and initiates replication due to the invasion of the host cell’s DNA to create new copies of the virus.

Patients
- The two prevalent human viruses are HSV-1 and HSV-2.

Diseases caused by the viruses include cold sores, genital herpes, herpes stromal keratitis (causes vision loss in the primary infection), meningitis (inflammation of the layers of the brain), and encephalitis (inflammation of the brain itself).
Immune responses are crucial in controlling HSV, but the virus can evade them.
Immune response can contribute to pathogenesis, as seen in stromal keratitis and encephalitis.
Genetic variations in humans can explain different likelihood of getting the severe form of the HSV disease.
HSV has two stages of replicating known as, lytic and latent.
- Latency occurs in neurons (type of cell that receives and sends messages from the body to the brain) and can lead to disease during primary infection or reactivation of the infection
- Lytic cycles occurs when the virus introduces its genetic material into a host cell (cell held by an infected person) and starts replication due to the invasion of the virus into the host cell’s DNA to create new copies of the virus.

Herpes simplex virus

Small blisters can erupt on the skin on the upper lip

Causes [2]
- 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’

Risk factors [5]
- 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

Presentations [6]
- 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

Investigations [2]

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

Differential diagnosis [7]
- 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

Management [6]
- Medical Students
  - Mucocutaneous herpes simplex infection:
    - Isolated infections may go untreated without consequences.
    - Treatment options: Acyclovir, valacyclovir, or famciclovir, especially for primary infection.
    - Acyclovir-resistant HSV is rare and occurs mainly in immunocompromised patients, treated with foscarnet.
    - Secondary bacterial infections: Topical antibiotics (mupirocin or neomycin-bacitracin) or systemic antibiotics (penicillinase-resistant beta-lactams).
    - Systemic analgesics for pain relief.
  - Gingivostomatitis (infection of the gums and the mouth) and pharyngitis:
    - Symptom relief: Topical anesthetics (dyclonine, benzocaine, viscous lidocaine).
    - Severe cases treated with acyclovir, valacyclovir, or famciclovir.
    - Herpes labialis:
    - Responds to oral and topical acyclovir.
    - Recurrent eruption duration can be decreased with penciclovir or famciclovir or valacyclovir
    - Acyclovir-resistant strains are resistant to penciclovir, famciclovir, and valacyclovir.
    - Docosanol may be effective
  - Herpetic whitlow:
    - Typically heals in 2 to 3 weeks without treatment.
    - Topical acyclovir not proven effective.
    - Use oral or IV acyclovir in immunosuppressed or severe cases.
  - Herpes simplex keratitis:
    - Treated with topical antivirals (trifluridine) under ophthalmologist supervision.
  - Herpes simplex CNS infection:
    - Encephalitis: Acyclovir
    - Viral meningitis: Treated with IV acyclovir, generally well-tolerated.
- Patients
  - Herpes simplex infection affecting the skin:
    - Infections that occur once may go untreated without consequences.
    - Treatment options including antivirals, Acyclovir, valacyclovir, or famciclovir, especially for primary infection.
    - Acyclovir-resistant HSV is rare and occurs mainly in patients with weakened immune systems, treated with foscarnet (an antiviral)
    - Secondary bacterial infections: Topical antibiotics (mupirocin or neomycin-bacitracin) or systemic antibiotics (penicillinase-resistant beta-lactams).
    - Systemic analgesics for pain relief.
  - Gingivostomatitis (infection of the gums and the mouth) and pharyngitis (inflammation of the pharynx):
    - Symptom relief: Topical anesthetics (dyclonine, benzocaine, viscous lidocaine).
    - Severe cases treated with acyclovir, valacyclovir, or famciclovir.
    - Herpes labialis (rash affecting the skin and mucous membranes eg. lips):
    - Responds to oral and topical acyclovir.
    - Recurrent eruption duration can be decreased with penciclovir or famciclovir or valacyclovir
    - Acyclovir-resistant strains are resistant to penciclovir, famciclovir, and valacyclovir.
    - Docosanol cream (antiviral cream) may be effective when used 5 times a day.
  - Herpetic whitlow (skin infection caused by herpes simplex virus):
    - Typically heals in 2 to 3 weeks without treatment.
    - Topical acyclovir not proven effective.
    - Use oral or IV acyclovir in immunosuppressed or severe cases.
  - Herpes simplex keratitis (vision loss caused by herpes simplex virus)
    - Treated with topical antivirals (trifluridine) under ophthalmologist supervision.
  - Herpes simplex affecting the central nervous system infection:
    - Encephalitis: Acyclovir
    - Viral meningitis: Treated with IV acyclovir, generally well-tolerated.
Complications [8]
- 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

Herpes simplex virus

Severe inflammation with ulcer formation and bloody crusts (right upper lip) found on a person with a weakened immune system

Myths behind herpes simplex virus [9]
- 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

Questions you may want to ask your doctor
- 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?