Lesson
Build the Immune Enteropathy
Celiac disease is a permanent immune-mediated response to dietary gluten in a genetically susceptible person. The small intestine is the principal injury site, but the clinical consequences extend throughout the body.
- Gluten peptides
- HLA-DQ2 and HLA-DQ8
- Tissue transglutaminase
- Villous atrophy
- Malabsorption
Wheat, barley, and rye supply the trigger while the patient is consuming gluten.
Tissue transglutaminase modification and antigen presentation support an adaptive immune response.
Inflammation, crypt hyperplasia, and villous atrophy reduce absorption and create systemic consequences.
Begin with susceptibility and exposure
Gluten proteins from wheat, barley, and rye supply immunogenic peptides. Most affected patients carry HLA-DQ2 or HLA-DQ8, but these haplotypes are common and do not establish the diagnosis by themselves.
Connect transglutaminase to adaptive immunity
Tissue transglutaminase modifies gluten peptides, which can be presented to T cells in a compatible HLA context. The resulting immune response drives intestinal inflammation and supports production of disease-associated antibodies.
Read the mucosal injury
Increased intraepithelial lymphocytes, crypt hyperplasia, and villous atrophy reduce absorptive surface. Histology must be interpreted with serology, diet status, and competing causes because villous injury is not unique to celiac disease.
Translate injury into physiology
Iron, folate, calcium, vitamin D, and other nutrients may be affected. Diarrhea, weight loss, anemia, low bone density, growth failure, and extraintestinal symptoms can follow even when abdominal symptoms are mild.
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Lesson
Recognize the Full Clinical Spectrum
Celiac disease may present through the gut, skin, blood, bone, liver, nervous system, fertility, or growth. Case finding depends on recognizing patterns rather than waiting for a single classic phenotype.
- Diarrhea and bloating
- Iron deficiency
- Bone disease
- Dermatitis herpetiformis
- Growth and reproduction
Diarrhea, pain, bloating, weight loss, nausea, or constipation can appear across ages.
Iron deficiency, low bone density, elevated liver tests, neuropathic symptoms, and fatigue can dominate.
Family history, type 1 diabetes, thyroid disease, IgA deficiency, and growth concerns support case finding.
Recognize gastrointestinal presentations
Chronic diarrhea, steatorrhea, abdominal pain, bloating, weight loss, nausea, and constipation can occur. Children may present with constipation, poor growth, delayed puberty, irritability, or abdominal distention.
Find extraintestinal disease
Iron-deficiency anemia, folate deficiency, low bone density, fractures, elevated aminotransferases, neuropathic symptoms, dental enamel changes, aphthous ulcers, headache, and fatigue can bring the patient to care.
Include reproductive presentations
Delayed menarche, unexplained infertility with recurrent miscarriage, and other menstrual disturbances can prompt celiac evaluation in the appropriate context. These findings have many causes and do not diagnose celiac disease. For confirmed disease, coordinate preconception and pregnancy care to maintain the gluten-free diet and correct folate and other nutritional deficits; dietary treatment does not guarantee fertility or pregnancy outcomes.
Use risk context
A first-degree relative with confirmed celiac disease, type 1 diabetes, autoimmune thyroid disease, selective IgA deficiency, and selected genetic syndromes can increase pretest probability. Testing remains guided by the clinical context.
Do not collapse the differential
Irritable bowel syndrome, inflammatory bowel disease, infection, pancreatic insufficiency, food intolerance, medication injury, and other enteropathies can overlap. A gluten-free response alone does not prove celiac disease.
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Lesson
Preserve Accuracy Before Changing the Diet
Serology is most informative while the patient is eating gluten. Starting a gluten-free diet before testing can lower antibody concentrations and complicate confirmation.
- tTG-IgA
- Total IgA
- IgA deficiency
- Gluten-containing diet
- Pretest probability
Testing after gluten withdrawal can reduce antibody concentrations and diagnostic sensitivity.
The total IgA result determines whether an IgA-based negative screen can be trusted.
High-probability disease can require biopsy even when screening serology is negative.
Test during gluten exposure
Measure tissue transglutaminase IgA while the patient is on a regular gluten-containing diet. Do not ask a patient to begin a gluten-free diet before the diagnostic plan is established.
Measure total IgA
Concurrent total IgA identifies patients in whom an IgA-based assay may be falsely reassuring. In IgA deficiency, use an IgG-based strategy such as tTG-IgG or deamidated gliadin peptide IgG according to the diagnostic pathway.
Interpret probability, not a number alone
A negative tTG-IgA with normal total IgA has strong rule-out value when pretest probability is low or moderate. High clinical suspicion can still justify endoscopy with duodenal biopsy.
Avoid obsolete shortcuts
Native antigliadin antibody testing is not the preferred modern screening strategy. A positive result requires confirmation in the correct clinical and histologic context rather than immediate lifelong dietary treatment.
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Lesson
Confirm the Diagnosis in the Right Context
For most patients, diagnosis integrates serology with upper endoscopy and multiple duodenal biopsies. Genetics and nonbiopsy pathways answer narrower questions.
- EGD
- Duodenal bulb
- Distal duodenum
- HLA exclusion
- Selected nonbiopsy criteria
Multiple specimens reduce the chance that patchy injury is missed.
Villous injury is interpreted with serology, gluten exposure, medicines, and competing enteropathies.
Absence of compatible HLA can rule out disease; presence does not prove it.
Sample the duodenum adequately
Upper endoscopy should obtain multiple specimens because injury can be patchy. Current ACG guidance describes one or two biopsies from the bulb and four from the distal duodenum.
Use histology with context
Villous atrophy and intraepithelial lymphocytosis support celiac disease when the patient is exposed to gluten and serology fits. Infection, immune deficiency, medication injury, and other enteropathies remain in the differential.
Use HLA testing mainly to exclude
Absence of a celiac-compatible HLA haplotype makes celiac disease very unlikely and can clarify discrepant or already gluten-free cases. Presence is common and does not confirm disease.
Respect the limits of nonbiopsy diagnosis
Under ESPGHAN 2020, selected children may avoid biopsy with tTG-IgA at least ten times the assay upper limit and positive EMA-IgA in a second blood sample during gluten intake, with family agreement and pediatric specialist supervision. Symptoms and HLA testing are not mandatory for this pathway; lower titers or an IgG-based result do not meet these criteria. Under ACG 2023, adults generally require biopsy; symptomatic adults unable or unwilling to undergo endoscopy may receive a likely diagnosis with tTG-IgA above ten times the assay upper limit and positive EMA in a second sample.
Identify the newer European adult pathway
ESsCD 2025 conditionally permits diagnosis without biopsy in selected adults younger than 45 with initial tTG-IgA at least ten times the assay upper limit. Confirm serology in a separate sample while gluten intake continues. A positive second sample is confirmatory under this pathway; it is not the pediatric EMA requirement. Decisions belong in specialist care with shared discussion.
Keep the exclusion criteria visible
Do not use the European no-biopsy pathway when bleeding, dysphagia, obstruction, or other warning signs require investigation for an alternative condition. Do not apply it automatically at age 45 or older. Name the guideline being followed rather than blending European, ACG, and pediatric criteria.
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Lesson
Build a Sustainable Gluten-Free Diet
A strict lifelong gluten-free diet is the disease-modifying treatment. Success requires more than a prohibited-food list because nutrition, cost, cross-contact, culture, and daily routines determine whether the plan is livable.
- Wheat, barley, and rye
- Less than 20 ppm
- Cross-contact
- Gluten-free oats
- Expert dietitian
FDA-regulated gluten-free claims use a less-than-20-ppm threshold and ingredient rules.
Shared fryers, toasters, surfaces, flour dust, and preparation systems can transfer gluten.
Nutrition, culture, cost, food access, oats, and unnecessary restriction require individual planning.
Remove the disease trigger
Avoid wheat, barley, rye, and ingredients derived from them unless processed and labeled in a manner that meets gluten-free requirements. Malt commonly derives from barley and requires careful label review.
Understand the US food claim
FDA-regulated food labeled gluten-free must contain less than 20 parts per million of gluten and meet ingredient restrictions. A voluntary claim does not eliminate the need to assess the product and the patient's context.
Prevent cross-contact
Shared fryers, toasters, cutting surfaces, bulk bins, flour dust, condiments, preparation tools, and restaurant workflows can introduce gluten. The response should be practical risk reduction, not indiscriminate food avoidance.
Use oats deliberately
Gluten-free oats are appropriate for most patients, but contamination and a small risk of avenin sensitivity require monitoring for symptoms and serologic relapse when introduced.
Partner with an expert dietitian
A dietitian experienced in celiac disease should assess adherence, nutritional adequacy, food access, culture, eating patterns, and avoidable restriction. Dietitian interview remains the standard adherence assessment.
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Lesson
Repair Deficits and Protect Long-Term Health
Removing gluten stops the trigger, but established deficiencies and preventive-care gaps still require direct assessment and treatment.
- Iron and folate
- Vitamin D and calcium
- Bone density
- Growth
- Pneumococcal vaccination
Blood counts, iron, folate, B12, vitamin D, calcium, and other tests follow the phenotype.
Replace documented deficits and track skeletal risk, weight, growth, and pubertal development.
Pneumococcal prevention follows current age, risk, prior-dose, and asplenia guidance.
Assess likely deficiencies
Use history, examination, blood counts, iron studies, folate, vitamin B12, vitamin D, calcium, liver tests, and other studies in proportion to the presentation. Replace documented deficits while the intestine heals.
Protect the skeleton
Evaluate calcium and vitamin D intake, fracture history, menopausal status, glucocorticoid exposure, and other bone risks. Plan DXA from individual risk: severe malabsorption, marked weight loss, fragility fracture, or other osteoporosis risks justify assessment. ESsCD Part 2 recommends baseline DXA after a year of gluten-free treatment in higher-risk adults; its discussion allows earlier assessment at diagnosis when warranted. Correct calcium and vitamin D deficits and assess for osteomalacia before osteoporosis medication.
Follow children as children
Track height, weight, growth velocity, pubertal development, symptoms, serology, and nutrition. Catch-up growth is an outcome, not a reason to stop follow-up.
Review immunization
ACG suggests pneumococcal vaccination for patients with celiac disease. The specific regimen should follow current age, risk, prior-vaccine, and functional-asplenia guidance rather than an outdated fixed schedule.
Avoid untargeted replacement
A gluten-free label does not make a supplement necessary or safe. Choose replacement from a documented need, product quality, interactions, and a monitoring endpoint.
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Lesson
Treat Dermatitis Herpetiformis Without Missing Systemic Risk
Dermatitis herpetiformis is an intensely pruritic celiac-associated blistering eruption. A gluten-free diet treats the underlying disease; dapsone can control skin symptoms quickly but does not heal the gastrointestinal component.
- Pruritic grouped lesions
- Gluten-free diet
- Dapsone
- Hemolysis
- Blood and liver monitoring
A strict gluten-free diet addresses both intestinal and skin disease over time.
Dapsone can rapidly reduce pruritus and lesions but does not heal intestinal disease.
Check G6PD before treatment; monitor CBC, hemoglobin and liver function. New cyanosis, serious rash, fever or weakness requires urgent assessment.
Recognize the phenotype
Dermatitis herpetiformis commonly produces intensely pruritic grouped papules or vesicles on extensor surfaces. Scratching can obscure intact blisters. Direct immunofluorescence of uninvolved skin next to a lesion is the key diagnostic test; it is a different specimen from a lesional biopsy for routine histology or a duodenal biopsy for enteropathy.
Keep the diet foundational
A strict gluten-free diet addresses the intestinal and skin disease but skin improvement can be slow. Dapsone may provide rapid symptom control while dietary treatment takes effect.
Use the label deliberately
The US label starts adults at 50 mg daily and describes individualized titration within 50 to 300 mg daily; this range is not an automatic escalation target. EADV guidance also describes a cautious start at 25 mg once or twice daily. Select and titrate under specialist supervision, then reduce to the lowest effective maintenance dose.
Obtain baseline safety tests
Measure G6PD activity before starting dapsone. Obtain a baseline CBC and hemoglobin, assess liver function and the clinical risk from anemia or cardiopulmonary disease. Correct severe anemia first. Normal G6PD activity does not eliminate the risk of hemolysis or methemoglobinemia, so it does not replace ongoing monitoring.
Anticipate hematologic toxicity
Dose-related hemolysis and methemoglobin formation can occur with or without G6PD deficiency and may be worse with G6PD deficiency. Severe anemia should be corrected, hemoglobin monitored, and cardiopulmonary disease considered.
Schedule and act on blood counts
The US label recommends CBCs weekly during the first month, monthly for six months, and then every six months when feasible. Increase monitoring when risk or interacting therapy warrants it. A significant decline in white cells, platelets, or blood-cell production requires dapsone discontinuation and intensive clinical follow-up.
Respond to warning symptoms
New fever or sore throat can signal agranulocytosis; cyanosis, dyspnea, or marked fatigue can signal methemoglobinemia or hemolysis. Hold treatment and seek urgent clinical assessment rather than waiting for the next scheduled blood count. A serious new rash, jaundice, or motor weakness also needs prompt withdrawal and evaluation.
Monitor beyond hemoglobin
The label calls for frequent complete blood counts, baseline and subsequent liver-function monitoring when feasible, and urgent response to fever, sore throat, pallor, purpura, jaundice, new rash, cyanosis, dyspnea, or muscle weakness. Dapsone can also falsely lower HbA1c.
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Lesson
Resolve Medication Gluten Questions by Exact Product
Medication excipient concerns should be handled precisely. Broad warnings that every tablet may contain harmful gluten can produce unnecessary fear, nonadherence, and delayed treatment.
- Exact NDC or product
- Inactive ingredients
- Wheat starch
- DailyMed
- Manufacturer confirmation
Manufacturer, strength, dosage form, imprint, and NDC distinguish products with different excipients.
Review DailyMed, OTC inactive ingredients, and manufacturer information when needed.
Most US oral medicines contain no or virtually no gluten, so unverified fear should not stop needed care.
Begin with the current FDA position
FDA reports that most oral drug products contain no or virtually no gluten and knows of no currently marketed US oral drug products with wheat gluten or wheat flour intentionally added. A small number may use wheat starch.
Match the exact product
Generic names do not identify excipients. Verify manufacturer, strength, dosage form, imprint, NDC when available, and the actual dispensed product before reviewing inactive ingredients.
Use current product information
DailyMed labeling and the OTC Drug Facts inactive-ingredient section can support review. If the source, manufacturing process, or product identity remains uncertain, contact the manufacturer or pharmacy supply chain.
Calibrate the risk message
FDA estimates that even rare wheat-derived ingredient use would contribute very little gluten per oral dose. Patients with unusual sensitivity, refractory disease, or unresolved product information need individualized review, not automatic discontinuation of clinically necessary medicine.
Document the resolution
Record the exact product, source checked, conclusion, date, and contingency if the manufacturer changes. Recheck after a product switch because inactive ingredients can differ.
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Lesson
Measure Recovery Beyond Symptom Relief
Symptoms can improve before serology or mucosa, and serology does not perfectly predict healing. Follow-up should measure the domains that matter rather than treating one normal result as completion.
- Dietitian review
- tTG trend
- Nutrient recovery
- Growth
- Mucosal healing
Dietitian interview remains the standard adherence assessment and can find both exposure and overrestriction.
Falling tTG supports response but does not independently prove mucosal healing.
Persistent disease and selected adult follow-up can justify repeat duodenal assessment.
Establish a baseline
Record symptoms, weight, growth in children, diet, key deficiencies, serology, bone risk, vaccination status, and comorbid autoimmune disease. A baseline makes later improvement interpretable.
Use expert dietary assessment
Combine an expert dietitian interview with symptoms and serology. ACG 2023 advises against routine gluten-detection devices in food or biospecimens. ESsCD Part 2 (2026) supports selected stool or urine gluten immunogenic peptide testing when symptoms persist or adherence is uncertain. These tests reflect recent ingestion; a negative sample neither excludes intermittent exposure nor proves mucosal healing.
Schedule reassessment
Arrange early review rather than waiting for symptoms to recur. ESsCD Part 2 suggests adult visits at 4-6, 12, and 24 months, followed by every 1-2 years for stable patients. Recheck prior laboratory abnormalities and nutrition; serology is included at 12 months. Persistent symptoms or deficits require earlier, more frequent assessment. Pediatric follow-up must also track growth and puberty.
Trend serology thoughtfully
Falling tTG supports reduced immune activity and adherence, but symptoms and serology correlate imperfectly with mucosal healing. A normalized antibody result does not prove healed intestine.
Consider mucosal reassessment
Endoscopy with biopsy is useful when symptoms persist or recur despite a gluten-free diet. In asymptomatic adults, follow-up biopsy after about two years can be considered through shared decision-making; routine follow-up biopsy is not recommended for asymptomatic children.
Define success broadly
Meaningful recovery can include symptom control, corrected anemia, nutrient repletion, weight or growth recovery, improved bone health, normalized liver tests, and sustained function without excessive dietary restriction.
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Lesson
Investigate Persistent Disease Systematically
Persistent or recurrent symptoms after treatment are common enough to require a process. Refractory celiac disease is rare and should not be diagnosed before the original diagnosis, diet, and competing conditions are reassessed.
- Inadvertent gluten
- Diagnostic review
- Competing disorders
- Repeat biopsy
- Refractory celiac disease
Review original gluten exposure, serology, biopsy quality, HLA context, and alternative enteropathies.
Dietary review and phenotype-directed testing address contamination, intolerance, IBS, SIBO, pancreatic disease, and colitis.
Villous atrophy despite verified long-term treatment requires specialist classification and complication assessment.
Reconfirm the diagnosis
Review original serology, gluten exposure at testing, endoscopy, biopsy location and interpretation, HLA context when relevant, and alternative causes of villous atrophy.
Assess dietary exposure without blame
Inadvertent gluten is a common explanation. An expert dietitian should review foods, supplements, restaurants, shared preparation, medicines, and overly restrictive compensatory behaviors.
Test competing explanations selectively
Lactose or fructose intolerance, irritable bowel syndrome, microscopic colitis, pancreatic insufficiency, small-intestinal bacterial overgrowth, inflammatory bowel disease, infection, and medication effects can produce persistent symptoms.
Use repeat endoscopy when needed
Ongoing symptoms, malabsorption, weight loss, anemia, or concerning laboratory change can require repeat EGD with biopsies to assess healing and identify persistent enteropathy or another disorder.
Explain malignancy risk proportionately
Lymphoma and small-bowel malignancy are recognized complications, but the absolute cancer risk in non-refractory celiac disease remains low. ESsCD guidance does not recommend extra routine cancer screening without clinical suspicion. New alarm findings warrant investigation; the much higher lymphoma risk in type II refractory disease should not be applied to every person with celiac disease.
Distinguish refractory subtypes
Specialist tissue testing distinguishes type I, with a generally normal intraepithelial lymphocyte phenotype, from type II, with an aberrant clonal population and greater lymphoma risk. Symptoms alone cannot assign the subtype. Classification, nutritional support, and exclusion of malignant complications belong in an experienced center.
Understand specialist treatment
Open-capsule budesonide is a first-line option for type I refractory disease and may be used in selected type II disease. Evidence is largely observational. This specialist formulation strategy is not permission to open or crush any budesonide product; the exact regimen and monitoring must be prescribed.
Refer suspected refractory disease
Refractory celiac disease means persistent symptoms or malabsorption with villous atrophy despite strict gluten-free treatment for at least 12 months after other causes are excluded. It is rare, has serious complications, and requires expert multidisciplinary care.
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Module practice
Check the connections.
Each attempt draws 10 questions from the complete 36 question bank.
Each attempt draws a fresh set and rearranges the answer choices.
References
Current clinical foundation.
Core source material was synthesized with the following contemporary guidance. Verify local policy and current guidance before applying clinical information.
- ESsCD adult celiac guideline Part 2 (2026): management, follow-up and complex disease.
- EADV S2k guideline: diagnosis and therapy of dermatitis herpetiformis (2021).
- ESsCD 2025 adult celiac disease guideline, Part 1: diagnostic approach.
- American College of Gastroenterology: Diagnosis and Management of Celiac Disease
- FDA: Questions and Answers on Gluten-Free Food Labeling
- FDA: Medications and Gluten
- DailyMed: Dapsone Tablets
- ESPGHAN 2020: Pediatric Celiac Diagnosis
- CDC: Pneumococcal Vaccine Recommendations