An earlier study also found that intradermal gluten injections caused skin reactions. The test was conducted within the layers of the skin of celiac patients. One-third of these patients were seen to develop reactions. However, this study did not account for gluten-rich cosmetic products applied on the surface of the skin. In fact, not one study has proven this thus far.
Dermatitis herpetiformis patients have also been tested with intradermal gluten injections. Nevertheless, studies have failed to witness skin reactions even when the disease is already the skin manifestation of celiac. This further implies that DH’s celiac is not worsened by cosmetic products applied on the surface of the skin. Ingesting the gluten is still the main culprit.
Yet another study has proven that ingesting gluten is what initiates a severe response. This time it comes as atopic dermatitis. Expectedly, having a gluten-free diet resolved dermatitis while reintroducing it brings the condition back. Clearly, the presence or absence of gluten in the small intestine is still the primary trigger of celiac disease.