To the Editor.—
In their article on dermatitis herpetiformis, Olbricht et al1 state that dermatitis herpetiformis is a skin disorder of unknown cause. This is not correct. The rash clears after withdrawal of gluten from the diet2 and recurs on reintroduction of gluten.3 Thus, by anybody's definition, the cause of the rash is gluten and is known.
Fry L, Leonard JN, Griffiths CEM. The Cause of Dermatitis Herpetiformis. Arch Dermatol. 1987;123(3):293. doi:10.1001/archderm.1987.01660270025002