The lips may undergo changes in size, color, and surface. Some of these changes may indicate a medical problem. Other changes are harmless. With aging, the lips may grow thinner.
Lip sores (ulcers) have various causes. A lip sore with hard edges may be a form of skin cancer (see Types of Oral Cancer; see also Lips and Sun Damage). Sores may also develop as a symptom of other medical conditions, such as erythema multiforme, recurrent oral herpes simplex virus infection (cold sores), or syphilis.
Spots on the lips may occur. Multiple, small, scattered brownish-black spots may be a sign of a hereditary disease called Peutz-Jeghers syndrome, in which polyps form in the stomach and intestines. Rarely, smokers develop noncancerous brown spots on the lips near where the cigarette is held. Freckles and irregularly shaped brownish areas (melanotic macules) are common around the lips and may last for many years. These marks are not cause for concern.
Kawasaki disease, a disease of unknown cause that usually occurs in infants and children 8 years old or younger, can cause dryness and cracking of the lips and reddening of the lining of the mouth.
Other common lip changes include
With inflammation of the lips (called cheilitis), the lips may become painful, irritated, red, cracked, and scaly.
Most commonly, irritation and inflammation involve the lips and skinfolds at the corners of the mouth (called angular cheilitis), typically if the person
- Has dentures that do not separate the jaws adequately
- Has worn down the teeth excessively, resulting in less space between the upper and lower teeth
- Has a Candida or a Staphylococcus aureus infection
- Has a deficiency of vitamin B2 or iron in the diet
Treatment consists of replacing the dentures, which helps reduce the folds at the corners of the mouth, or restoring proper tooth size with partial dentures, crowns, or implants. Infections are treated with drugs applied to the corners of the mouth. Vitamin B2 deficiency and iron deficiency can be treated by taking dietary supplements.
Other forms of cheilitis usually affect the outside surface of the lips and the lips' border with the skin. Causes include infection, sun damage, drugs or irritants, allergy, or an underlying condition. Treatment includes petroleum jelly applied to the lips and elimination or treatment of underlying conditions.