Chronic, Recurring Canker Sores in the Mouth

Acute cases of sores in the mouth usually lasts for up 2 weeks until the ulcers heal and completely resolve. However many oral canker sore sufferers report chronic or recurring cases of mouth ulcers, either within the same area of the initial lesion or surrounding areas.

Chronic mouth sores are considered to be any individual mouth ulcer or group of ulcers that lasts for several weeks to months. Recurring mouth sores are mouth ulcers that heal and then develop again immediately after the condition resolves or recur  several days to weeks later. Chronic and recurring mouth sores are often indicative of other pathology in the area, repeated trauma or exposure to chemical irritants and allergens or systemic causes of mouth ulcers.

Recurrent attacks of mouth sores are common, with 2 to 3 ulcers occurring simultaneously during each attack. In severe cases, sufferers may experience in excess of 10 mouth sores occurring simultaneously causing significant discomfort and severely affecting eating and drinking. While most mouth sores, especially minor mouth ulcers, heal within 2 weeks, cases of major mouth ulcers (large than 1 centimetre in diameter) may take several weeks to months to heal without proper treatment. These cases may be considered as chronic mouth sores however the duration of the ulcer is due to the size, other contributing factors and causes and the lack of proper treatment.

Any chronic or recurring attacks of mouth sores should be differentiated from mouth lesions in other conditions causing inflammation of the mouth (stomatitis).

Oral Erythema Multiforme

Oral erythema multiforme is the painful inflammation of the mouth and presents with diffuse, bleeding lesions particularly affecting the lips and inner cheek. Other symptoms of erythema multiforme include high fevers, malaise and joint pain. Other lesions may be noted on the skin, conjunctiva of the eye and genitals.

Oral Herpetic Lesions

Oral herpetic lesions causes recurrent painful vesicles (small fluid filled ‘bumps’) which can affect the mouth cavity, inner and outer lip. Other symptoms associated with oral herpetic lesions include gingivitis (inflammation of the gums) fever, malaise and swollen lymph nodes of the neck. Herpetic lesions may also burning and itching of the lip with the feeling that the lip is swollen or enlarged. However no significant swelling of the lip may be noticeable.

Oral Thrush

Oral thrush (candidiasis) which appears as white, slightly raised patches which usually begins on the tongue and spreads to inner cheek, palate, gums, tonsils or throat. The tissue of the mouth may appear red and inflamed  and any attempt to remove or scrape the white patches may cause bleeding. Oral thrush is more commonly seen in immunocompromised patients especially in HIV/AIDS and in certain chronic conditions.

Kawasaki Syndrome

Kawasaki syndrome usually affects infants and children below the age of 5 years causing a skin rash similar to urticaria (hives) , fever, lymphadenopathy (swollen lymph nodes) and may also cause joint pain and inflammation of the blood vessels initially seen as paleness of the fingernails and toenails. Signs and symptoms affecting the mouth include red, dry and cracked lips and a fiery red tongue often described as ‘strawberry red’. Kawasaki syndrome should only be diagnosed by a medical practitioner and requires specialist care.

Acute Necrotizing Ulcerative Gingivitis

Acute necrotizing ulcerative gingivitis (Vincent’s infection) are ulcerative lesions of the gingival papillae , the thin section of the gum between adjacent teeth. These lesions may become necrotic meaning that the affected tissue may die, decompose and erode and this more often occurs in cases of HIV infection.


Acrodynia occurs in children and may cause mouth ulcers with profuse salivation and bruxism (grinding of the teeth and clenching of the jaw). Acrodynia is caused by mercurial toxicity (excessive or prolonged  intake or ingestion of mercury).

It may at times be difficult to different chronic mouth sores from other conditions affecting the oral cavity.  Typically mouth ulcers (aphthous stomatitis) rarely affects the hard palate and gum and are usually  not accompanied by other signs and symptoms. Severely infected ulcers may cause fevers and swollen glands of the neck (cervical lymphadenopathy) and jaw if left untreated and complicated by other factors or pre-existing conditions. Chronic and recurrent mouth sores that are not responding to treatment should be investigated by a medical practitioner to exclude mouth ulcers as a sign of other more serious conditions.

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