Cheilitis is an inflammation of the lips, which could be acute or chronic. The inflammation primarily arises in the vermilion zone but may extend to surrounding skin and less commonly, to the oral mucosa. It may be caused by a multitude of factors, including contact irritants or allergens, chronic sun exposure, and nutritional deficiencies, as well as by various cutaneous and systemic illnesses.[1]

Eczematous cheilitis could be a result of exogenous factors (irritant contact cheilitis, allergic cheilitis) or endogenous factors (atopic cheilitis).

Dry, chapped lips: Frequent exposure to hot or dry winds can cause loss of plasticity of keratin in vermillion, leading to sores and dry, scaly lips. The patient might get into the habit of chronic licking of lips to pick up scales, which further aggravates the problem.[2] It is also referred to as irritant contact cheilitis.

Allergic Contact Cheilitis: A delayed-type hypersensitivity reaction to allergens that come in contact with the lips can cause inflammation of the lips. It is also known as lipstick cheilitis since several ingredients found in lipsticks may act as irritants. The most common cosmetic sensitizers identified by patch testing include fragrances, Myroxylon pereirae, and nickel. However, some ingredients unique to lipsticks may also cause lip dermatitis. For example, castor oil, colophony, shellac, azo dyes, sesame oil, preservatives, ozonated olive oil, propolis, and copolymers. Apart from lipsticks, allergic contact cheilitis can be caused by a variety of other substances that come into contact with lips. They could be found in mouthwashes, toothpastes, and even food.[3] Lipstick cheilitis may present as persistent irritation and scaling, sometimes associated with edema and vascularization, confined to vermillion or extending beyond in some cases. Cheilitis caused by food may involve the skin around the mouth.[4]

Atopic Cheilitis: Patients with a history of atopy or atopic dermatitis commonly have associated atopic cheilitis. It presents with dryness, erythema, scaling, and fissuring of lips.[5]

Angular Cheilitis: Angular cheilitis, also known as angular stomatitis or perlèche, is an acute or chronic inflammation of the skin and adjacent labial mucosa at the angles of the mouth. It manifests as a roughly triangulararea of erythema and edema at one, or more frequently both,angles of the mouth. [6]The most common cause of angular cheilitis in adults is a fungal infection, Candida albicans, and less commonly, Staphylococcus aureus. Poor oral hygiene, ill-fitting dentures, or absence of teeth as in the elderly can lead to excessive moisture and maceration from saliva leading to these infections. Less commonly, the nutritional deficiencies, particularly those of riboflavin (B2), niacin (B3), pyridoxine (B6), folate (B9), iron, and general protein malnutrition, may produce smooth, shiny, red lips associated with angular stomatitis, collectively known as cheilosis. [7]

Infective cheilitis:

Viral cheilitis: It is mainly due to the herpes simplex virus, especially type 1. The primary herpes infection (herpetic gingivostomatitis) combines post-vesicular erosive and crusted cheilitis with diffuse stomatitis leading to dysphagia, perioral vesicles, fever, and cervical lymphadenopathy. Recurrence of oral herpes affects the lips in most cases. It manifests as a cluster of blisters accompanied by a burning sensation. Next, the vesicles erode to leave behind crusted erosions that resolve in a week.[2]

Bacterial Cheilitis: The most common cause of bacterial cheilitis is infection with group A Streptococcus or Staphylococcus.[6]

Mycotic cheilitis: Cheilitis caused by candida manifests with erythema and painful edema of the lips, sometimes with fissures, and it is usually accompanied by acute (pseudomembranous candidiasis) or chronic stomatitis, and/or angular cheilitis. The diagnosis is confirmed by taking a specimen for mycological examination.[8]

Parasitic cheilitis: Leishmaniasis is a possible cause of cheilitis in endemic regions. It gives the appearance of an erythematous papule or plaque that gradually enlarges and then ulcerates or a permanent lip enlargement (macrocheilia).[9]

Actinic Cheilitis: Actinic Cheilitis (also known as solar keratosis of the lip or actinic keratosis) originates from the proliferation of atypical epidermal keratinocytes due to chronic sun exposure. It is a premalignant condition and occasionally progresses to squamous cell carcinoma.[10][11] Most cases are observed in outdoor workers, fair-skinned individuals, and during the fourth to eighth decades of life. The lower lip border receives the highest ultraviolet radiation, being at right angle to the midday sun rays and poorly protected by melanocytes. Clinical symptoms are varied, depending upon the stage of the disease, and may include erythema, edema, plaques, and nodules and later develop into ulceration as the lesion becomes malignant. Notably, the lesions have a characteristic "sandpapery" feel to touch.[12]

Drug-induced cheilitis: Systemic retinoids such as etretinate and isotretinoin cause dryness, erythema, scaling, and cracking of the lips (may include angles of mouth) in almost all the patients. Less frequently, it may also be caused by any other drugs that cause dryness of mouth and lip.[2]

Glandular cheilitis: It is a rare, chronic inflammation with tumefaction and sometimes suppuration of salivary glands at the lower lip. The most common clinical form is the simple cheilitis glandularis, which manifests as a moderate thickening of the lower lip with inflammatory dilated gland duct orifices, from which mucous saliva can be squeezed easily. [13][14]Older males are most commonly affected, but can also be seen in young individuals and women. In the more severe suppurative form (Volkmann’s cheilitis), the lip is enlarged considerably and persistently (macrocheilia) and is associated with pain and tenderness. Crusts and scales cover the surface, beneath which the salivary duct openings may be found. Eventually, it results in a deep-seated infection that may cause the formation of abscess and fistulous tracts.[13]

Cheilitis granulomatosis: Cheilitis granulomatosis is a persistent, idiopathic, nontender granulomatous inflammation of one or both lips. The initial manifestation is sudden diffuse or nodular swellings involving the upper lip, the lower lip, and one or both cheeks in decreasing incidence. Early attacks cause edema of lips that usually subsides in days to hours; however, recurrent attacks may lead to a persistent increase in swelling, leading to firm, rubber-like consistency of lips. [15]Cheilitis granulomatosis can be isolated, idiopathic (Miescher cheilitis granulomatosis), or associated with various systemic conditions (sarcoidosis, Crohn’s disease, tuberculosis). The complete form of Melkersson Rosenthal syndrome combines cheilitis granulomatosis, peripheral facial paralysis, and a fissured tongue with loss of taste sensation.[15][16]

Eczematous cheilitis most common form of cheilitis and is more prevalent in people with a history of allergies. [5]

Angular cheilitis/infective cheilitis may present at any age with an equal male to female ratio but is especially likely in older individuals wearing dentures. Children suffering from these forms have a history of recurrent infections or immune defects.[17]

Actinic cheilitis is more prevalent in geographic areas with high ultraviolet (UV) irradiation, and in fair-skinned men who work outdoors (e.g., fishermen, farmers) in their fourth to the eighth decade of life. Certain genetic conditions associated with increased susceptibility to solar damage may predispose individuals to acquire actinic cheilitis at an early age (e.g., xeroderma pigmentosum, oculocutaneous albinism).[18][19]

Glandular cheilitis is a rare form of cheilitis, more prevalent in older males, but individuals in younger age and women also may be affected. The cause is unknown, but several factors have been identified, including atopy, infection, chronic exposure to the sun, repeated licking, and use of tobacco.[20][21]

Cheilitis granulomatosis is rare. It primarily affects young adults but can occur at any age, with equal ration in male to female. It is idiopathic. However, there are several predisposing factors, including food allergy, genetics, infection, and atopy.[22]

Eczematous cheilitis could be due to loss of plasticity, delayed-type hypersensitivity or atopy, depending upon the type.[2]

Angular cheilitis is a result of by softening of tissue from excessive moisture from saliva and secondary infection with Candida albicans or, less frequently, Staphylococcus aureus.[6]

Actinic Cheilitis originates from the proliferation of atypical epidermal keratinocytes due to chronic sun exposure.[10][11]

Drug-induced cheilitis is mainly caused by excessive dryness of mouth and lips.[2]

Glandular cheilitis results from fibrosis surrounding the salivary glands. Dense chronic inflammatory infiltrates may be found in severe cases.[13]

Cheilitis granulomatosis results from long-standing edema and perivascular inflammation of lip and facial tissue. As the infiltrates become more dense, pleomorphic and small focal granulomas are formed, indistinguishablefrom systemic granulomatosis.[15][16]