**Question:** True about celiac disease -

A. It is a condition caused by an autoimmune response to gluten
B. It primarily affects the skin and hair
C. It is a genetic disorder primarily affecting children
D. It is a viral infection

**Core Concept:** Celiac disease is an autoimmune disorder triggered by gluten consumption in genetically susceptible individuals. Gluten is a protein found in wheat, barley, and rye. In celiac disease, the immune system mistakenly attacks the small intestine, damaging the villi (tiny projections that absorb nutrients) and leading to malabsorption and potential malnutrition.

**Why the Correct Answer is Right:** A is the correct answer because celiac disease is primarily triggered by the immune response to gluten, which is a protein found in wheat, barley, and rye. The damage to the small intestine's villi in celiac disease is due to this autoimmune response.

**Why Each Wrong Option is Incorrect:**

B is incorrect because celiac disease primarily affects the small intestine, not the skin and hair. The skin and hair symptoms seen in celiac disease are often due to malabsorption and nutrient deficiencies rather than a direct effect of gluten on skin and hair.

C is incorrect because although celiac disease does have a genetic component, it primarily affects the small intestine and is triggered by gluten consumption, not primarily genetic. Children are not exclusively affected; celiac disease can occur at any age.

D is incorrect as celiac disease is not a viral infection. It is an autoimmune disorder triggered by gluten consumption in genetically susceptible individuals. Viral infections typically present with different symptoms and mechanisms.

**Clinical Pearl:** Celiac disease is a common condition, with an estimated prevalence of 1% in the general population. It is often underdiagnosed, as symptoms can be non-specific and overlap with other disorders. A thorough history and physical examination, along with appropriate investigations like endoscopy and biopsy, are essential for diagnosing celiac disease. Consultation with a gastroenterologist may be beneficial for proper management and treatment of celiac disease.