What causes blisters at the corners of the mouth?

Cracked lips or blisters at the corners of the mouth may be caused by factors such as internal heat ("shang huo"), angular cheilitis, or herpes virus infection. It is recommended to visit a hospital for examination and receive appropriate treatment based on the specific cause.

1. Internal Heat ("Shang Huo")

If a patient frequently consumes spicy or irritating foods, stays up late, or maintains poor dietary habits over a long period, it can lead to "internal heat," triggering a stress response in the body and resulting in blisters at the corners of the mouth. Under medical guidance, medications such as Niuhuang Jiedu Tablets, Compound Honeysuckle Granules, or Qingre Jiedu Capsules may be used. It is advisable to maintain a light diet and drink plenty of water regularly.

2. Angular Cheilitis

Picky eating or unbalanced diet may lead to malnutrition, particularly deficiency in B-complex vitamins, making the individual prone to angular cheilitis, which can cause blisters at the corners of the mouth. Adjusting the diet by including foods rich in B vitamins—such as peanuts, black rice, bananas, kiwifruit, and fish—can help replenish these nutrients and relieve symptoms.

3. If the patient has oral ulcers, fluids secreted from ulcerated oral mucosa may easily cause inflammation at the corners of the mouth, leading to blister formation. Under medical supervision, treatments such as watermelon frost spray, Cetylpyridinium Iodide lozenges, or Bingbor Powder may be used.

In addition, blisters at the corners of the mouth may also result from infection with the herpes simplex virus, which causes lesions in the oral mucosa. Under a doctor's guidance, antiviral medications such as Acyclovir capsules, Valacyclovir Hydrochloride tablets, or Ribavirin granules may be prescribed for treatment.