Herpes Simplex (fever blisters)
Fever blisters are painful small grouped blisters with surrounding redness that occur in outbreaks on specific locations of the body. They most commonly appear on the lips, but can also be seen on the nose, buttocks, thigh, or shoulder. The outbreaks typically last 1 or 2 weeks and then gradually resolve, sometimes with residual scars. Outbreaks then sporadically recur, always in the same specific area of the skin. Some people experience frequent outbreaks (every 1 or 2 months). Others go years between flare-ups.
The eruption is caused by reactivation of dormant herpes simplex virus that resides within a specific nerve root. Once activated the virus migrates out of the nerve, causing bumps and blisters. Most of us get exposed to this virus in childhood, causing a brief illness with sore throat, blisters and fever. After this primary episode, the virus becomes integrated in the root of a nerve in only some individuals, who may then later develop recurrent herpes simplex outbreaks. Genital herpes simplex is caused by a different related virus that can also lead to repeated outbreaks on the genital skin.
Certain conditions tend to precipitate herpes simplex outbreaks. Sunburn or prolonged sun exposure, local trauma or injury and significant physical or emotional stress are some of the possible triggering factors. Effort should be made to limit these conditions that might cause fever blisters to activate. Use sunscreens regularly on the affected areas.
The blisters do contain active virus and it is possible to transmit this infection to others via contact with blister fluid. Care should be taken to avoid direct skin contact with the affected area.
There are no consistently effective creams or ointments that can significantly reduce the duration of herpes simplex outbreaks. However, there are several antiviral pill medications that can reduce the duration of an outbreak, getting it to resolve faster than it would without any treatment. To be effective, these medicines have to be started within 24 to 48 hours of the beginning of the outbreak. If itching, numbness or tingling usually precedes outbreaks, then the pills can be started as soon as these warning symptoms occur. The pills are then continued for 5 days. If episodes recur frequently (more than 6 per year), then daily suppressive antiviral medication may be required for months at a time.
Back to Patient Teaching article list