Cold sores, or fever blisters, are a common viral infection usually caused by herpes simplex virus type 1 (HSV-1), though HSV-2 can also cause them through oral-genital contact.

They are highly contagious, spreading through direct contact like kissing, or indirect contact via shared items such as towels, utensils, or lip balm. Touching a sore and then another body part can also spread the virus.

An outbreak typically follows stages: tingling or itching a day or two before appearance, blister formation near the lips, rupture into painful sores, and eventual scabbing. While sores heal in 7–10 days, the virus remains dormant and can reactivate.

Triggers include stress, sun exposure, hormonal changes, illness, and a weakened immune system. There’s no cure, but antiviral pills like acyclovir or valacyclovir can shorten outbreaks. Topical creams, pain relievers, and moisturizing balms can ease discomfort.

Prevention involves avoiding close contact during outbreaks, not sharing personal items, using lip sunscreen, and maintaining overall health. Seek medical advice if outbreaks are frequent, severe, spreading, or affecting daily activities, especially with a weakened immune system.

Interestingly, new research has linked oral health to Alzheimer’s disease. Studies suggest gum disease bacteria, P. gingivalis, may contribute to Alzheimer’s development. Its toxic enzymes, gingipains, have been found in brains of both diagnosed patients and those with Alzheimer’s pathology but no dementia diagnosis.

Researchers believe this points to brain infection occurring before cognitive decline, not simply as a result of poor oral care in later stages. In mice, a compound called COR388 reduced harmful protein buildup and brain inflammation.

While human treatments are still unproven, experts stress the importance of exploring such approaches, given the lack of new dementia therapies in over 15 years.