The most common cause of lower lip discoloration is staining from nicotine. Cigarettes, cigars and chewing tobacco can all stain the lower lip, especially among chronic users, and can also lead to oral cancers that produce growths or marks on the lips.
A number of other health and dermatological conditions can also lead to discoloration in the pigment of the lower lip.
Anemia and iron deficiency often result in universal paleness of the skin, but the difference is most noticeable in the lips. Other symptoms might include fatigue, dizziness and nausea. To eliminate the discoloration and restore iron levels, a doctor might prescribe iron supplements or blood transfusions.
Also called liver spots, these brown or black spots on the lips result from prolonged sun exposure. They are not medically dangerous, but they often become a cosmetic nuisance. To prevent further spots, avoiding sun exposure is essential.
Certain viruses, including oral herpes and lymphomas, leave white blemishes on the lower lips. The white spots are sometimes accompanied by itching, burning or soreness. Patients should visit their doctors as soon as they see signs of an oral viral infection.
When the lower lip comes into contact with an allergen, swelling and discoloration may result. Lipsticks, beverages and other substances introduced to the mouth are usually the culprit.