What causes the upper lip to turn black while the lower lip remains normal?

Generally, darkening of the upper lip with a normal lower lip may be caused by factors such as pigmentation, local irritation, post-inflammatory hyperpigmentation after cheilitis, digestive system dysfunction, or inadequate cardiac blood supply. If discomfort occurs, it is recommended to seek timely medical evaluation and treatment at a正规 hospital. Specific causes are analyzed as follows:

1. Pigmentation

Long-term sun exposure or frequent friction on the upper lip can activate melanocytes in the area, leading to pigment deposition. Apply sunscreen when going outdoors, use a gentle lip balm to protect the lips, avoid repeatedly rubbing the upper lip with hands, and consume more fruits and vegetables rich in vitamin C.

2. Local Irritation

Long-term use of lipstick containing irritating ingredients or habitual licking of the upper lip can damage the lip mucosa and lead to pigmentation. Discontinue use of suspected lipsticks, correct lip-licking habits, moisturize with fragrance-free lip balms, and avoid consuming excessively hot or spicy foods that may irritate the lips.

3. Post-Cheilitis Pigmentation

The upper lip may have previously suffered from cheilitis, leaving localized pigmentation after inflammation subsides. Follow medical advice to apply hydroquinone cream, azelaic acid cream, or vitamin E cream. Avoid re-irritation of the lips and take proper sun protection measures when outdoors.

4. Digestive System Dysfunction

Gastrointestinal disorders may cause toxin buildup in the body, manifesting as darkening of the upper lip. Maintain regular eating habits and avoid overeating. Follow medical guidance to take medications such as Bifidobacterium triple viable capsules, Jianwei Xiaoshi tablets, or Domperidone tablets, and ensure smooth bowel movements.

5. Inadequate Cardiac Blood Supply

Poor cardiac perfusion leads to impaired circulation in the lips, and due to the unique vascular distribution in the upper lip, it may appear darker. Seek immediate medical evaluation and follow doctor’s instructions to take medications such as enteric-coated aspirin, nitroglycerin tablets, or Compound Danshen dripping pills. Avoid strenuous exercise and emotional excitement.

In daily life, maintain clean and well-moisturized lips and choose safe lip care products; maintain regular sleep patterns and a balanced diet while reducing intake of irritating foods; undergo routine health check-ups to monitor gastrointestinal and heart health; and promptly consult a doctor for symptom evaluation if any abnormalities occur.