Cold sores are caused by a virus called herpes simplex type 1 (HSV-1). Some people have no symptoms from this infection, but others develop painful and unsightly cold sores that last for a week or more. Cold sores usually occur outside the mouth -- on the lips, chin, and cheeks, or in the nostrils. When they do occur inside the mouth, it is usually on the gums or the roof of the mouth.
There is no cure for cold sores. Medicines can relieve some of the pain and discomfort associated with the sores. These include ointments that numb the blisters, antibiotics that control secondary bacterial infections, and ointments that soften the crusts of the sores.
Variants in two genes - APOE and C21orf91 (cold sore susceptibility gene 1) have been associated with cold sores. A study1 found that people carrying the C-allele (or G-allele on the FWD strand) of C21orf91 rs1062202 are more likely to have cold sores twice or more annually than people carrying the T-allele (or A-allele on the FWD strand).
HSV-1, herpes simplex virus 1