Aphthous ulcers

[...]in a minority of patients, recurrent aphthae can be an oral manifestation of systemic diseases or deficiencies (box). [...]ask about genital ulcers and symptoms of uveitis (pain, blurry vision, light sensitivity, tearing, or redness of the eye) in Middle Eastern or South East Asian patients to exclude Behcet's disease (vasculitis). If present, they may be indicative of skin conditions affecting the oral mucosa, such as lichen planus (itchy lesions with Whickham's striae), lupus erythematosus (butterfly rash), pemphigus vulgaris (blistering, potentially fatal), or benign pemphigoid (blistering in genitalia and ocular conjunctiva).