Infections that can cause painful blisters on or around the lips or genitals
- Unprotected sex with multiple partners is a risk factor for genital herpes
- Age, gender, and genetics are not significant factors
The highly contagious herpes simplex viruses cause a number of different disorders characterized by small, painful blisters on the skin and mucous membranes, most commonly on or around the lips (see Cold sore) or genital area (see Genital herpes). Herpes simplex virus (HSV) infection is transmitted by contact with a blister.
Infection with HSV does not give immunity against future attacks. The viruses remain dormant in the nerves and may be reactivated by stress or illness. Outbreaks are more frequent and severe in people with reduced immunity, such as those with AIDS (see HIV infection and AIDS).
What are the types?
Several types of HSV have been identified. The two most common types are HSV1 and HSV2. HSV1 usually causes infections of the lips, mouth, and face; and HSV2 typically causes infections of the genitals. However, there is considerable overlap between the two types: conditions that are typically caused by HSV1 may sometimes be caused by HSV2 and vice versa.
Most people have been infected with HSV1 by the time they are adults. In most cases, the initial infection produces no symptoms, but some children may develop blisters on the inside of the mouth (see Stomatitis), and children with the skin disorder eczema may develop eczema herpeticum (see Eczema in children). After the initial infection, the virus becomes dormant but may reactivate periodically later in life, causing cold sores.
HSV2 is usually sexually transmitted and causes genital herpes. This condition, like cold sores, tends to recur. HSV2 can also cause a life-threatening infection in a newborn baby if the baby comes into contact with the mother’s genital blisters during birth (see Congenital infections).
Both HSV1 and HSV2 can affect the eyes, causing inflammation and a discharge (see Conjunctivitis). In rare cases, infection with HSV results in severe inflammation of the brain (see Viral encephalitis).
What might be done?
HSV infection can be diagnosed from the appearance and site of the blisters. Mild cold sores can usually be treated with over-the-counter topical antiviral drugs. If you have genital herpes or severe or recurrent cold sores, you may be given oral antiviral drugs. The earlier these drugs are given, the more effective they are likely to be.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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