Erythroplakia and erythroleukoplakia causes Autoimmune disease or kawasaki's , anemia , canakers sores, drug addict or B12 defeciency
You start with the simpler most of diagnoses of recurrent apthous ulcers in iron and b12 def. Then progress based on additional symptoms, if any. History of smoking, hpv infection (multiple partners), persistent for more than 3 weeks etc. U mentioned it occurs once a month and is extensively painful. Erythroplakia or premalignant oral lesions are NOT RECURRENT, and are usually asymptomatic with some cases of mild burning sensation. They are progressive and stubborn. More than 3 weeks CONTINUOUSLY?? Then take a biopsy.
Again start with the simplest explanations. Congenital syphilis is usually in infants, an uncommon late variety does exist but presents with an entire armada of symptoms by the age 2 to 6 years. Hutchinson triad, frontal bossing, mullberry molars, hepatospleenomegaly, anaemia jaundice and a vastness of other symptoms need to be present.
