Lips can become chapped or dry when they are exposed to the sun, wind, and cold or dry air. A lip balm containing petroleum or beeswax will provide a barrier and help seal in moisture.
More moisture is lost through the lips than through any other part of the face or body.
When the lips lose moisture, the skin covering them can become tight and start to split.
What not to do
It's very tempting to pick and bite off flakes of dried skin, but this will only make the lips bleed and heal more slowly. Irritating the skin around the mouth may also trigger a cold sore if you're prone to getting them.
It's also tempting to keep licking dry or cracked lips. However, this will only dry your lips more, as the saliva evaporates and the repeated licking or wetting "washes" the natural grease off the skin.
How to treat dry or sore lips
The best thing to do for dry or sore lips is to regularly apply a lip balm containing petroleum or beeswax. You may need to try a few different products before you find one that works for you.
Choose a balm with an additional sun protection factor (SPF) of at least 15 to help protect your lips in the sun.
A lip balm will act as a shield to protect your lips against the sun, wind, cold or dry air. It will trap in moisture and seal cracks against infection.
Avoid lip balms in pots, as repeatedly dipping your finger into the balm can introduce germs.
Covering your lips with a scarf when you're outside during the winter can also help prevent dry lips.
When dry lips become inflamed
Sometimes, dry lips can become inflamed and feel sore. The medical term for inflamed lips is cheilitis.
Lips usually become inflamed as a result of mild irritation, although inflammation can be the result of an infection caused by dirt, bacteria or fungi entering cracks in the skin of the lips.
If you have red, sore lips and think they are infected, see your GP. They may prescribe an antibiotic or antifungal cream to treat the infection. This may also contain 1% hydrocortisone (steroid medication) to reduce the inflammation.
If the corners of the mouth are red and sore, you probably have a type of inflammation called angular cheilitis. This is often caused by bacteria or fungi and is treated with ointments applied to the area.
Angular cheilitis can sometimes be a symptom of a type of eczema called contact dermatitis, and is more common in people who wear dentures.
It is also more common in older people where the creases around the corners of the mouth become more pronounced, as saliva can build up in the crevices and irritate the skin.