Saliva keeps the mouth and lips moist, which prevents cracking, infection and ulceration of these modified skin surfaces. Salivary moisture also keeps the mouth clean and aids in the sense of taste by bathing the taste buds. Paired salivary glands in front of the ears and along the jaw produce saliva. Diseases, conditions and medical treatments that reduce the production of saliva or obstruct its release can cause dry mouth and lips.
Medications and Drugs
Medications remain one of the most common causes of dry mouth, or xerostomia. The National Institute of Dental and Craniofacial Research reports that decreased saliva production and associated dry mouth are possible side effects of more than 400 over-the-counter and prescription medicines.
Commonly used medications that may cause dry mouth and lips include antihistamines, decongestants, drugs used to treat ADHD, certain types of antidepressants, beta-blocker heart and blood pressure medications, diuretics, antiseizure medicines, antispasmodics, antipsychotics and antinausea drugs. Dose adjustments, a change to another medication or saliva replacement medication may be warranted for severe dry mouth symptoms.
Notably, the illicit drug methamphetamine causes dry mouth. Chronic xerostomia associated with protracted methamphetamine use is a significant contributing factor to the severe gum disease and rampant tooth decay seen in long-term users, reports the Merck Manual Online Medical Library. Poor nutrition and grinding of the teeth are also contributing factors. As with other forms of dry mouth, lip dryness typically accompanies this condition. Methamphetamine-related xerostomia, commonly known as "meth mouth," often causes irreparable damage to the teeth.
Sjögren's Syndrome
Sjögren's syndrome is an autoimmune disease in which the salivary glands and tear-producing lacrimal glands are erroneously attacked and destroyed by the immune system. Dry mouth and eyes are the classic symptoms of Sjögren's syndrome. Dryness of the nasal and vaginal tissues and dry skin also commonly occur with Sjögren's syndrome, which affects an estimated 1 to 4 million Americans, according to the National Institute of Neurological Disorders and Stroke.
Head and Neck Radiation
Cancers of the mouth, tongue, nose and throat are commonly treated with radiation therapy. This form of cancer therapy often damages the salivary glands, causing a decrease in saliva production within approximately one week of beginning treatment, notes the National Cancer Institute.
The salivary glands often receive high doses of radiation during head and neck cancer treatment, which frequently leads to permanent, marked reduction in saliva production. To minimize the adverse effects of chronic dry mouth on the teeth and gums, doctors often prescribe saliva replacement medication. Lip moisturizers can help prevent cracking of the tissue, which often occurs at the corners of the mouth.
References
- National Institute of Dental and Craniofacial Research: Dry Mouth
- Merck Manual for Healthcare Professionals: Xerostomia
- National Institute of Neurological Disorders and Stroke: Sjögren's Syndrome
- National Cancer Institute: Oral Complications of Chemotherapy and Head/Neck Radiation
- The Merck Manual of Health & Aging: Dry Mouth
