Herpes

Herpes simplex, commonly known as herpes, is a viral infection caused by the herpes simplex virus (HSV). The disease is characterised by the site of infection, predominantly affecting the mouth or genitalia. Two major types of HSV are HSV-1, which typically causes oral herpes, and HSV-2, which usually leads to genital herpes.

Signs and Symptoms

HSV infection manifests in various forms. Oral herpes involves the face or mouth, leading to small blisters often referred to as cold sores or fever blisters. Genital herpes affects the genitalia, forming blisters that break open and turn into small ulcers. These symptoms usually resolve within two to four weeks. In addition to blisters, symptoms may include fever, muscle pains, swollen lymph nodes, and headaches. Other forms of HSV infection can affect different parts of the body, such as herpetic whitlow (fingers or thumb), herpes simplex keratitis (eye), herpesviral encephalitis (brain), and neonatal herpes (newborns).

Oral herpes of the lower lip. Note the blisters in a group marked by an arrow.

Pathophysiology

After initial infection, HSV becomes latent in sensory nerves, residing there lifelong. Recurrence of symptoms can be triggered by factors such as decreased immune function, stress, and sunlight exposure. HSV is transmitted through direct contact with infected body fluids or lesions. Asymptomatic shedding occurs in many infected individuals, contributing to the spread of the virus even when symptoms are absent.

Herpes infection

Diagnosis

Diagnosing HSV is based on clinical presentation and can be confirmed through laboratory tests such as PCR, viral cultures, and blood tests for HSV antibodies. Primary infection often presents with distinctive sores and acute gingivitis, especially in orofacial herpes. However, diagnosing genital herpes can be challenging due to the similarity of symptoms with other conditions, such as fungal infections and dermatitis.

Treatment

While there is no cure for HSV, antiviral medications like aciclovir and valaciclovir can reduce the severity and frequency of outbreaks. Analgesics and topical anaesthetics such as lidocaine can alleviate pain and itching. For severe complications, antiviral therapy is very important to manage symptoms and prevent further spread.

The antiviral medication aciclovir

Prevention

Preventing HSV transmission involves avoiding direct contact with infected lesions and body fluids. Condom use significantly reduces, but does not eliminate, the risk of genital herpes transmission. For pregnant women with HSV, antiviral therapy and elective caesarean sections can reduce the risk of neonatal herpes. Daily antiviral medication for infected individuals can also decrease the likelihood of transmission to uninfected partners.

Epidemiology

HSV-1 and HSV-2 are widespread, with global infection rates between 60% and 95% for adults. HSV-1 is typically acquired during childhood, while HSV-2 is more common in adults, especially in populations with lower socioeconomic status. Most HSV-2-infected individuals are unaware of their infection, which underscores the need for better diagnostic and public health measures.

Signs and Symptoms of Specific Types

Herpetic Gingivostomatitis

Often the initial presentation of HSV infection, it is more severe than herpes labialis and is characterised by inflamed papules and vesicles around the mouth.

Herpetic gingivostomatitis

Herpes Labialis

Recurrent HSV-1 infection presenting as cold sores on the lips.

Herpes labialis

Herpes Genitalis

Clusters of inflamed papules and vesicles on the genitalia.

Herpes genitalis

Herpetic Whitlow and Herpes Gladiatorum

Painful infection affecting the fingers or thumbs, and sometimes the toes or nail cuticle.

Herpetic whitlow in a young child

Herpesviral Encephalitis and Herpesviral Meningitis

Life-threatening conditions caused by HSV-1 and HSV-2, respectively.

Herpesviral encephalitis

Herpes Esophagitis

Characterised by painful and difficult swallowing, often in immunocompromised individuals.

Herpes esophagitis