 Herpetiform ulcers , ( also termed stomatitis herpetiformis , or herpes @-@ like ulcerations ) is a subtype of aphthous stomatitis so named because the lesions resemble a primary infection with herpes simplex virus ( primary herpetic gingivostomatitis ) . However , herpetiform ulceration is not caused by herpes viruses . As with all types of aphthous stomatitis , it is not contagious . Unlike true herpetic ulcers , herpetiforme ulcers are not preceded by vesicles ( small , fluid filled blisters ) . Herpetiforme ulcers are less than 1 mm in diameter and occur in variably sized crops up to one hundred at a time . Adjacent ulcers may merge to form larger , continuous areas of ulceration . Healing occurs within fifteen days without scarring . The ulceration may affect keratinized mucosal surfaces in addition to non keratinized . Herpetiform ulceration is often extremely painful , and the lesions recur more frequently than minor or major aphthous ulcers . Recurrence may be so frequent that ulceration is virtually continuous . It generally occurs in a slightly older age group than the other subtypes , and females are affected slightly more frequently than males . 
