Myths vs facts: tTG IgA and Haut

tTG-IgA (tissue transglutaminase antibodies) is a well-established biomarker for celiac disease. A common myth is that a positive tTG-IgA test automatically means celiac disease with skin involvement (dermatitis herpetiformis). Fact: tTG-IgA is specific for celiac disease, but not every celiac patient develops skin symptoms. Dermatitis herpetiformis is a distinct manifestation caused by IgA deposits in the skin and is also associated with tTG-IgA. Another myth: tTG-IgA can be reliably diagnosed from a home blood test alone. Fact: A positive result always requires confirmation via duodenal biopsy and/or HLA typing, as false positives can occur (e.g., in other autoimmune conditions). Moreover, consumer tests without medical interpretation can lead to misinterpretation. The evidence linking tTG-IgA to celiac disease is strong (human-strong), but the translation to skin symptoms is not universal. Safety note: If celiac disease or dermatitis herpetiformis is suspected, a specialist (gastroenterology/dermatology) should always be consulted before starting a gluten-free diet.