A 4-year-old boy presents with an itchy rash and chronic diarrhea. What conditions does he likely have?

The presentation of an itchy rash and chronic diarrhea in a 4-year-old boy strongly suggests possible celiac disease, particularly when paired with dermatitis herpetiformis, which is a classic skin manifestation associated with this intestinal condition. Celiac disease arises due to an abnormal immune response to gluten, leading to inflammation and malabsorption in the intestines, which perfectly correlates with chronic diarrhea.

Dermatitis herpetiformis is characterized by a blistering, itchy rash that often appears symmetrically on the elbows, knees, and buttocks. Its association with celiac disease is well-documented, making this combination likely when the symptoms of skin irritation and gastrointestinal distress present together.

Other conditions listed do not match the clinical picture as closely. For example, while atopic dermatitis is indeed associated with itching and eczema-like rashes, it does not typically involve diarrhea as a prominent feature unless other gastrointestinal conditions are also present. Crohn's disease can lead to diarrhea but is less likely to cause a related itchy rash. Hives and ulcerative colitis also do not logically connect the symptoms of an itchy rash and chronic diarrhea in the same manner as dermatitis herpetiformis and celiac disease do.

Therefore, the combination of dermatitis herpetiform