Cold sores are red, fluid-filled blisters that appear near the mouth or on other areas of the face. In rare cases, cold sores may appear on the fingers, nose, or inside the mouth. There is no cure for cold sores, and infections tend to reoccur without warning. Sores are contagious and may persist for more than one week.
What Causes Cold Sores?
Herpes simplex type 1 virus usually causes cold sores, and herpes simplex type 2 virus generally causes genital herpes. The actual sores are similar in appearance for both forms of the virus.
It is possible (though rare) for herpes simplex type 1 to cause sores on the genitals, and for herpes simplex type 2 to cause sores on the mouth.
Visible sores are contagious, but herpes may be spread even when sores can’t be seen. You can catch the herpes simplex virus by coming in contact with infected individuals. This may happen through kissing, sharing cosmetics, or sharing food. Oral sex may spread both cold sores and genital herpes.
Once you catch herpes simplex virus, it can’t be cured. Even after sores have healed, the virus remains dormant in your nerve cells, and new cold sores can appear at any time. Some affected patients report more frequent outbreaks when their immune systems are weak, such as during illness or times of stress.
Recognizing a Cold Sore
You may notice a tingling or burning sensation on your lips or face several days prior to the emergence of a cold sore. Once the sore erupts, you will see a red, raised blister full of fluid, which will usually be painful and tender to the touch.
The sore will remain for two to three weeks, and it is contagious until it crusts over. Your first cold sore may not appear for up to 20 days following infection with the herpes simplex virus.
In addition to one or several sores, you may experience any of the following symptoms during an outbreak:
- muscle aches
- swollen lymph nodes
Touching your cold sore before touching your eyes can cause eye infections. You should seek immediate medical care if you develop an eye infection during a cold sore outbreak. This is because infections caused by herpes simplex can lead to permanent vision loss if not treated promptly.
The initial infection with herpes simplex can cause more severe symptoms and complications, as your body hasn’t yet built a defense mechanism to the virus. Complications are rare, but do occur, especially in young children. Any of the following requires medical attention:
- high or persistent fever
- difficulty breathing or swallowing
- red, painful eyes with or without discharge
If you have eczema or a condition that compromises your immune system (such as cancer or AIDS), you face a higher risk of complications. If you do have any of these conditions, contact your doctor if you suspect you have contracted cold sores.
Treating Cold Sores
There is no cure for cold sores, but some people with herpes simplex rarely have outbreaks. If cold sores are bothersome, you may be able to control pain and promote healing with antivlral topical ointments such as acyclovir (Xerese, Zovirax) and penciclovir (Denavir). These tend to be most effective if applied when a sore first appears, and will need to be applied four to five times daily for four to five days.
Docosanol (Abreva) is an over-the-counter cream that, when applied several times daily, can shorten an outbreak by anywhere from a few hours to a day.
Oral antiviral medications include valacyclovir (Valtrex) and famciclovir (Famvir). These are available by prescription only.
There are also cold sore patches available for treating skin wounds. These patches contain a gel called hydrocolloid, and they cover the sore while it heals.
If you experience complications with cold sores, or your outbreaks are frequent, you may be prescribed antiviral medications to take regularly, regardless of whether or not you have an outbreak.
Symptoms may be eased by applying either ice or washcloths soaked in cold water to the blisters. Alternative treatments include stress-reduction techniques, taking lysine supplements, or using lip balm containing lemon extract during an outbreak.
Tips for Preventing Outbreaks
If you have a cold sore outbreak, wash your hands often and avoid skin contact with others to avoid spreading the virus. Sharing items that touch your mouth (like lip balm and food utensils) with others is not advised during an outbreak. You should also avoid touching your eyes and genitals, as herpes simplex can cause eye infections and genital herpes.