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Author: Dr Delwyn Dyall-Smith FACD, Dermatologist, 2010.
Allergic contact cheilitis is allergic contact dermatitis affecting the lip(s). It is due to a type IV hypersensitivity reaction following contact with an allergen and usually presents as an eczema-like inflammation of the outer lip or vermilion margin.
Allergic contact cheilitis is a common cause of lip inflammation and is more common than contact stomatitis, despite considerable overlap in allergen sources. Approximately one quarter of cases of chronic eczematous cheilitis are due to allergic contact.
Allergic contact cheilitis is more common in women than men. It can affect all age groups, but adults are more commonly affected than children. However the allergens involved vary in different age groups. These differences reflect the usage patterns of the different age groups and sexes. Lip cosmetics are the most common allergen source in women, and toothpastes in men. Medications are an important source of allergic contact cheilitis reactions in the elderly. Dental materials and oral hygiene products cause cheilitis in all age groups. Reactions to food mainly affect children. Patients are often also atopic.
Major sources of allergens causing contact cheilitis include:
Common allergen groups that cause contact cheilitis include:
Rarely, contact urticaria of the lip due to a low dose of a frequently used allergen may present as a cheilitis, e.g. flavouring in a toothpaste. Foods are a major cause of contact urticaria of the lips.
Allergic contact cheilitis usually presents as eczema-like changes on the vermilion margin or skin around the mouth. One or both lips may be red with dryness, scaling and cracking. The changes may be quite localised or affect the whole lip. Involvement of the angles of the mouth may also be seen (angular-cheilitis). The pattern of the reaction may give some clue as to the cause; for example allergy to a musical instrument will develop changes only in that part of the lip in contact with the instrument. Allergic contact cheilitis rarely affects the inner mucosal aspect of the lip.
The patient may report associated itch, burning or pain of the lips.
Pigmented allergic contact cheilitis is an uncommon variant and presents with pigmentation of the lip which persists after resolution of the eczema.
Clinical examination should include, in addition to the lips, the inside of the mouth and general skin. Atopic dermatitis is commonly associated with contact cheilitis.
Patch testing is the key to this diagnosis. Testing should include the standard series of patch test allergens as well as cosmetic and toothpaste series, and others suggested by the history. It is most important to also test the patient's own products and musical instruments if possibly relevant. Cosmetics are often applied ‘as is’, but sawdust from wooden instruments should be applied diluted to 10% in petrolatum. A significant number of patients react only to their own products. The relevance of positive results must be assessed, based on careful history taking and clinical examination. Multiple positive reactions are common.
Repeated open application test (ROAT) or start-restart testing may be required for a patient's own products due to irritation under occlusion in patch testing, such as with toothpastes.
Photopatch testing may also be useful when investigating cheilitis when routine patch testing is negative.
Should contact urticaria of the lip be suspected then prick/scratch testing is required.
It is common for patients with allergic contact dermatitis to have a second diagnosis such as atopic cheilitis or irritant contact cheilitis.
Avoidance of the allergen in all of its possible sources is the treatment. The reaction then usually settles quickly.
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