Cold sores, fluid-filled skin pustules or blisters, are caused by one of two viral infections. If you are infected with herpes simplex type 1 or type 2, cold sores may manifest around your lip, elsewhere on your face or on your genitals. While bothersome, the blisters typically clear up within a short period; no medical treatments are available to hasten their disappearance. The appearance of cold sores is no reason to interrupt your regular activities, including swimming in public pools.
Cold Sores and Contagion
Cold sores may spread the herpes simplex virus through direct contact. Usually, this happens when a sore becomes ruptured. For this reason, contagion is most common from contact that involves friction, such as during kissing, oral sex or sex. Transmission is less likely, though still possible, from a carrier of the virus who does not have any visible sores. By contrast, the virus cannot pass from one person to another through another material, so you cannot spread the virus by sharing a swimming pool, towels, cups or cutlery. Neither can it spread through blood.
Painful Cold Sores
If your cold sores are very painful, applying a cool or warm compress may relieve the pain or irritation. If the change in temperature soothes your pain, try swimming in cool water or wading in a warm hot tub to get the same effect.
Even though cold sores are viral in nature, it's advisable to care for their effects on your skin with some of the same basic techniques you would use with any other rupture or blemish. Keep the area clean and use a lip moisturizer or petroleum jelly to keep the skin from drying out, cracking or bleeding. Because long periods in the water while swimming can dry out your skin, apply a small amount of petroleum jelly or a heavy moisturizing ointment over the sore as a protective barrier before getting in the water.
Self-Consciousness and Stigma
If you're concerned about others seeing your cold sore, use a small amount of makeup over it. However, you should first dab it with petroleum jelly or a specialized cold sore cream, so the makeup clings to the topcoat of ointment. When going swimming, it's unlikely that your makeup will remain in place. Instead of trying to cover up the pesky sore, take heart in the fact that you are not alone; according to the National Institute of Dental and Craniofacial Research, between 45 and 80 percent of all Americans have had cold sores at some point in their lives.