[5] Counterintuitively, constant licking of the lips causes drying and irritation, and eventually the mucosa splits or cracks.

[8] Some children have a habit of sucking and chewing on the lower lip, producing a combination of cheilitis and a sharply demarcated perioral erythema.

[10] Also termed "solar cheilosis", actinic cheilitis is the result of chronic over-exposure to ultraviolet radiation in sunlight.

[11] It is especially common in people with light skin types who live in sunny climates (e.g., Australians of European ancestry), and in persons who spend a lot of time outdoors.

There are many possible causes, including nutritional deficiencies (iron, B vitamins, folate), contact allergies,[13] infections (Candida albicans, Staphylococcus aureus or β-hemolytic streptococci) and edentulism (often with overclosure of the mouth and concomitant denture-related stomatitis), and others.

Also termed "lip dermatitis",[14] eczematous cheilitis is a diverse group of disorders which often have an unknown cause.

[26] Impetigo (caused by Streptococcus pyogenes and/or Staphylococcus aureus), can manifest as an exfoliative cheilitis-like appearance.

A related condition is Melkersson–Rosenthal syndrome, a triad of facial palsy, chronic lip edema, and fissured tongue.

Common causes of drug-related cheilitis include Etretinate, Indinavir, Protease inhibitors, Vitamin A and Isotretinoin (a retinoid drug).

[11][32] Uncommon causes include Atorvastatin, Busulphan, Clofazimine, Clomipramine, Cyancobalamin, Gold, Methyldopa, Psoralens, Streptomycin, Sulfasalazine and Tetracycline.

[33] Also termed "cheilitis exfoliativa" or "tic de levres",[11] is an uncommon[24] inflammatory condition of the vermilion zone of the lips, which become painful and crusted.

[12][24] The keratin layer of the epidermis of the lips experiences a faster growth and death rate than normal and desquamates.

[26] Management consists mostly of keeping the lips moist and the application of topical corticosteroids ranging from hydrocortisone to clobetasol.

[36] Chelitis glandularis is a rare inflammatory condition of the minor salivary glands, usually in the lower lip, which appears swollen and everted.

[37][38] Suspected causes include sunlight, tobacco, syphilis, poor oral hygiene and genetic factors.

Cheilitis glandularis usually occurs in middle-aged and elderly males, and it carries a risk of malignant transformation to squamous cell carcinoma (18% to 35%).

[39] Plasma cell cheilitis appears as well defined, infiltrated, dark red plaque with a superficial lacquer-like glazing.