Cold sores, or fever blisters, are usually caused by herpes simplex virus type 1 (HSV-1), though HSV-2 can also spread through oral-genital contact. They are “highly contagious,” passing through kissing, shared items like towels or lip balm, or touching a sore and then another body part.

Outbreaks progress in stages: tingling or itching before appearance, blister formation near the lips, rupture into painful sores, and scabbing. They typically heal in 7–10 days, but the virus stays dormant and can return. Common triggers include stress, sun exposure, hormonal changes, illness, and a weak immune system.

There’s no cure, but antivirals such as acyclovir or valacyclovir can shorten outbreaks. Topical creams, pain relievers, and moisturizing balms help ease discomfort. Prevention includes avoiding close contact during outbreaks, not sharing personal items, using lip sunscreen, and staying healthy.

Doctors recommend seeking advice if sores are frequent, severe, spreading, or interfering with daily life—especially for those with weakened immunity.

Interestingly, new research links oral health to Alzheimer’s disease. Gum disease bacteria *P. gingivalis* and its toxic enzymes have been found in brains of patients. In mice, the compound COR388 reduced harmful proteins and inflammation, raising hope for future treatments.