Dermatitis - herpetiformis on the knee

This picture shows the knee of a person with a chronic inflammatory disease known as dermatitis herpetiformis. It produces red, raised (papular), small or large blisters (vesicles or bullae) that burn and itch intensely. Dermatitis herpetiformis develops suddenly, lasts for weeks to months, and may be associated with digestive diseases (such as Celiac disease).