According to HealthGuidance, smoking, hormonal imbalance, vitamin deficiency, iron build-up in the body, caffeinated beverages, hyper-pigmentation and allergic reaction can cause dark spots to appear on the lips. Sun exposure can also cause dark spots as UV rays cause spots of pigment, also called freckles, to appear on the skin. Dark spots may also be a sign of melanoma cancer.
While most dark spots are no cause for concern, new spots require evaluation by a medical professional or dermatologist, says New Health Guide. Although cancer of the lip is rare, it is a possibility. According to New Health Guide, cancer normally appears on the bottom lip and is more common in those who spend a great deal of time outdoors.
Most concerns associated with black lip spots are cosmetic. MD-Health.com recommends using lemon juice to lighten dark spots and lip balm containing sunscreen to prevent new spots from forming. Spots can also be covered up with lipstick. Since hot foods, tobacco, alcohol, iron supplements, tea and coffee can make spots darker, the site recommends avoiding these as well. Additionally, MD-Health.com recommends drinking plenty of water as dry lips can lead to the formation of new spots or make old ones get darker.