Toothpaste is a very common contributor to chapped lips, even though we may not consider it. Most toothpaste contains guaiazulene, which may cause a contact allergy.
Lipstick contains an ingredient called propyl gallate which can also cause a contact allergy, therefore causing chapped lips eventually.
Orange juice or any other juice from citrus fruits can irritate your lips. A photo-toxic reaction can occur on your lips that look like chapped lips.
We all use red dye in many products. Candy, lozenges, chewing gums, mouthwash, etc. all contain red dye that may cause allergies.
Various other lip care products besides lipstick are also a point of interest when it comes to pin-pointing allergic reactions. Many contain Phenylsalicylate (salol) which may be the cause for severe chapped lips.
Too much of vitamin A may also be the culprit behind your peeling lips. It does not matter if the source of your vitamin A comes from whole foods or supplements, if you are taking in more than 25,000 I.U. per day, then you might want to take a closer look at this.
In addition to excessive vitamin A, your body may be taking in too much Vitamin B12 supplements. As a result of this you develop an allergy to cobalt from taking your B12 supplements and this causes crusty and swollen lips.
Cinnamon flavoring can also cause lip chapping. This flavoring is found in candy, chewing gums, mouthwashes, etc.
Eating too many figs can also cause your allergic reaction due to photo-toxicity.
And interestingly enough, metal objects like paper clips and pocket change is a very likely cause of chronic chapped lips. An allergic reaction may show itself on your lips.