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Cold sore
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<p>A cold sore is a type of <a href="/facts/Herpes/8AQktlTV">herpes</a> <a href="/facts/Viral_disease/F1Tth6qP">infection</a> caused by the <a href="/facts/Herpes_simplex_virus/pStCydgY">herpes simplex virus</a> that affects primarily the <a href="/facts/Lip/cUlpthmx">lip</a>. Symptoms typically include a burning pain followed by small <a href="/facts/Blisters/qGhqaeQV">blisters</a> or <a href="/facts/Ulcer_(dermatology)/ALY0IW1n">sores</a>. The first attack may also be accompanied by fever, sore throat, and <a href="/facts/Enlarged_lymph_nodes/t7t4tEon">enlarged lymph nodes</a>. The rash usually heals within ten days, but the virus remains <a href="/facts/Dormancy/VqHprS5C">dormant</a> in the <a href="/facts/Trigeminal_ganglion/zJcSUs5s">trigeminal ganglion</a>. The virus may periodically reactivate to create another outbreak of sores in the mouth or lip. </p><p>The cause is usually herpes simplex virus type 1 (HSV-1) and occasionally herpes simplex virus type 2 (HSV-2). The infection is typically spread between people by direct non-sexual contact. Attacks can be triggered by <a href="/facts/Sunlight/WPkJRC7s">sunlight</a>, <a href="/facts/Fever/waVxR2Ac">fever</a>, <a href="/facts/Psychological_stress/eqat8pq9">psychological stress</a>, or a <a href="/facts/Menstrual_period/AY6Y9xxM">menstrual period</a>. Direct contact with the <a href="/facts/Genitals/c2ypY14E">genitals</a> can result in <a href="/facts/Genital_herpes/evzPRkxt">genital herpes</a>. Diagnosis is usually based on symptoms but can be confirmed with specific testing. </p><p>Prevention includes avoiding kissing or using the personal items of a person who is infected. A <a href="/facts/Zinc_oxide/P7sTyDez">zinc oxide</a>, <a href="/facts/Anesthetic/0xG7I2ou">anesthetic</a>, or <a href="/facts/Antiviral_medication/Xgbd2eI2">antiviral cream</a> appears to decrease the duration of symptoms by a small amount. Antiviral medications may also decrease the frequency of outbreaks. </p><p>About 2.5 per 1000 people are affected with outbreaks in any given year. After one episode about 33% of people develop subsequent episodes. Onset often occurs in those less than 20 years old and 80% develop <a href="/facts/Antibody/MX8pdTdP">antibodies</a> for the virus by this age. In those with recurrent outbreaks, these typically happen less than three times a year. The frequency of outbreaks generally decreases over time. </p>