Celiac disease is an autoimmune disorder where consuming gluten triggers an immune reaction that damages the lining of the small intestine. Gluten, a protein found in wheat, barley, and rye, prompts the body to mistakenly attack the small intestine’s villi. This damage impairs the gut’s ability to absorb nutrients, which is particularly detrimental to a child’s growth and development. Achieving a timely and accurate diagnosis is important to prevent long-term complications and ensure they receive the necessary dietary treatment.
Recognizing Symptoms in Children
The presentation of celiac disease in pediatric patients is highly varied, making recognition challenging. Children often exhibit classical gastrointestinal symptoms, which are typically more common in younger patients. These can include persistent diarrhea, abdominal pain, bloating, and chronic constipation.
The damage to the small intestine’s villi leads to malabsorption, resulting in non-classical symptoms that manifest outside of the digestive tract. Parents might observe a child experiencing failure to thrive or weight loss. Other indicators can include delayed puberty, unexplained iron-deficiency anemia, and defects in the dental enamel of permanent teeth. These signs emphasize why a high index of suspicion is necessary, as not all children present with the stereotypical digestive issues.
Essential Preparation for Accurate Testing
The most important step before initiating any diagnostic test is ensuring the child is actively consuming gluten. The immune system’s reaction to gluten produces the measurable antibodies and causes intestinal damage. If a child stops eating gluten before testing, the small intestine can begin to heal and antibody levels may drop, leading to a misleading false-negative result.
This requirement is often called a “gluten challenge” if the child has already been placed on a gluten-free diet. To ensure accurate results, the child must consume a sufficient amount of gluten, typically equivalent to about two slices of wheat bread daily, for six to eight weeks before the blood test. Attempting to diagnose the condition while the child is avoiding gluten makes the process unreliable and may necessitate a difficult reintroduction later on.
Initial Blood Screening
The diagnostic process begins with a blood test to check for specific autoantibodies in response to gluten. The Tissue Transglutaminase IgA (tTG-IgA) test is the primary and most cost-effective screening tool, measuring IgA antibodies that target the enzyme tissue transglutaminase.
It is important to measure the child’s total serum Immunoglobulin A (IgA) level. A selective IgA deficiency is common, and a low total IgA level can cause a false-negative result on the IgA-based tTG test. If an IgA deficiency is confirmed, the physician will use an IgG-based antibody test, such as the Deamidated Gliadin Peptide IgG (DGP-IgG) or the tTG-IgG, to screen for the disease. A significantly positive result indicates a high probability of celiac disease and warrants the next steps in confirmation.
Confirming the Diagnosis
The traditional method for confirming a diagnosis is an upper endoscopy with a small bowel biopsy. During this procedure, a camera is passed through the mouth to the small intestine, where multiple tissue samples are collected. A pathologist then examines these samples for the characteristic damage, known as villous atrophy, which confirms the diagnosis.
However, the European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) has established a non-biopsy pathway for children, which avoids the need for an invasive endoscopy in certain cases. This pathway can be used when a child has highly elevated tTG-IgA levels—specifically, ten times the upper limit of normal (ULN). This high antibody level, combined with a positive result for the Endomysial Antibody (EMA-IgA) test in a second blood sample, provides diagnostic certainty high enough to bypass the biopsy requirement.
If the tTG-IgA level is positive but below the 10x ULN threshold, or if the initial serology is otherwise inconclusive, the standard endoscopic biopsy remains necessary. Children who are IgA deficient and test positive on IgG-based tests are generally advised to proceed with the biopsy.