Celiac Disease
Celiac Disease Diagnosis
A person seeking preliminary diagnosis MUST be eating gluten. Specific antibody blood tests help identify the presence of CD and are the initial step in screening and should include the following tests:
- Endomysial antibody (EMA-IgA)
- Tissue transglutaminase antibody (tTG - IgA/IgG)
- Anti-gliadin antibody (AGA-IgG, AGA-IgA)
- Total serum IgA
The exception is children under the age of 2 years in which tTG and EMA may not be present. Consult your physician. It is essential that patients with positive antibody tests, and those with an IgA deficiency have a small bowel biopsy (which is performed endoscopically) to confirm the diagnosis and assess the degree of damage to the villi in the intestinal lining.
Blood tests can only screen for RISK of celiac disease and cannot confirm it. When blood tests and biopsy are inconclusive, testing for specific HLA (human leukocyte antigen) DQ2/DQ8 genes associated with celiac disease may be helpful. As an autoimmune disease, CD is the result of the interaction between genes and the environment (gluten). All the necessary genes to develop CD are not known; however, HLA DQ2 and/or DQ8 are absolutely necessary to develop CD. Since one-third of the population also have these genes, the presence of DQ2 or DQ8 does not imply that the person will develop CD, rather, that they have a genetic compatibility with CD. Genetic testing does not diagnose celiac disease – the absence of DQ2/DQ8 almost always rules it out. Patients should always consult with a physician to ensure proper diagnosis.
Dermatitis Herpetiformis (DH) is the skin manifestation of celiac disease characterized by blistering, intensely itchy skin. The rash has a symmetrical distribution and is most frequently found on the face, elbows, knees and buttocks. DH patients can have intestinal damage without obvious GI symptoms.
Dermatitis Herpetiformis (DH) is diagnosed by a biopsy of a skin lesion and staining for IgA in the tissues. More than 85% of DH patients have small bowel sensitivity to gluten. Everyone with DH needs to follow a gluten-free diet.
