Which of the following is the earliest change in intestine which occurs in Crohn’s disease?

Ref. Robbins Pathology. 9th edition. Page. 800   Crohns Disease Present with skip lesions Earliest lesion – Aphthous ulcers Can involve whole of GIT – Form oral cavity to amus Smoking is a risk factor Fissure, fistula seen Stricture seen Gross features – Creeping pad of fat, Cobblestone appearance Microscopy - Non caseating granuloma under microscopy, Transmural inflammation