My brother is suffering from chronic aphthos ulcers. he was treated symptomatically with topical prednisone as well as antibiotics. still no effect?

Apthous ulcers: A thorough evaluation for causes of aphthous ulcers will include a search for medical conditions that could delay healing, plus an evaluation of the mouth and teeth to identify any factors that are creating the ulcers. Treating any underlying conditions may be important for healing.

Chronic ulcers: There are prescription meds help reduce the intensity and duration but this a virus and there is no cure. Palliative treatments can help with discomfort, also modifying diet, exposure to irritants, trauma and reducing stress can help as well. See a dentist for prescription meds and use when earliest signs occur, may cut from 7-10 days to 3-5 days. Antibiotics only treat bacterial infections.

There is help: Actually there are some older meds that if taken regularly can significantly reduce the recurrence rate of these ulcers. I use Colcrys (colchicine) first. If that is not helpful, Dapsone may be effective. Speak with your doctor.