An aphthous ulcer is a shallow erosion with a yellow-white center surrounded by a narrow, red ring.
Aphthous ulcers have no blisters.
There may be one or several aphthous ulcers present. Twenty to sixty percent of the population have had aphthous ulcers at some time in their lives. People most frequently get them between the ages of 10 and 40 and they are often recurrent. Tingling or burning may precede the lesions by 24 hours. The acute painful phase lasts 3 to 4 days with complete healing in 7 to 10 days.