Some reasons for occasional numbness of the lips and tongue include medication side effects, food allergies, cold temperatures, low calcium levels and lack of blood flow to the area, notes Healthgrades. In rare cases, anaphylaxis, toxins or hyperventilation can cause numbness of the lips and tongue.
There are many causes of numbness to the lips and mouth, ranging from mild to life-threatening. It primarily results from irritation, compression or damage to the nerves leading to the area, according to Mayo Clinic. In some cases, it is due to muscle contractions, such as a result of calcium deficiency, or caused by an underactive thyroid. Numbness of the mouth and lips is a symptom of several diseases, including Lyme disease, multiple sclerosis and cancer, as noted by Healthgrades.
Patients who have received local anesthesia for dental surgery, such as wisdom tooth removal, may continue to experience numbness to the mouth and lips for some time once the medication wears off, as stated by WebMD. This is due to nerve inflammation in the jaw.
Treatment for numbness of the lips and mouth depends on its cause. Physicians need detailed symptom information and may conduct several tests before prescribing treatment, according to Mayo Clinic.