RESUMO
INTRODUCTION: Collagen colitis (CC) is a microscopic colitis diagnosed by mucosal biopsy and is extremely rare in children. PATIENT CONCERNS: We reported a child with severe persistent diarrhea that could not be relieved with traditional diarrheal treatment. No abnormalities were found after multiple colonoscopies. DIAGNOSES: A significant increase in total IgE levels was found in the patient's blood. He had a history of mild chronic allergic rhinitis and slightly intermittent wheezing. However, we found that the child had a hyperallergic reaction to multiple respiratory antigens and had mild pulmonary dysfunction. Finally, colonoscopy with biopsy identified the diagnosis of CC. INTERVENTION: Considering that a respiratory allergic reaction was one of the causes of diarrhea, anti-allergic treatment was given to the child, and his severe diarrhea was soon relieved. Corticosteroid treatment was suggested to the patient, but his parents firmly refused steroid therapy. According to the patient's specific allergic reaction to mites, desensitization treatment was finally chosen for him. OUTCOMES: After 1 year of desensitization for dust mites, the patient's respiratory symptoms improved, total IgE levels decreased, autoantibodies declined, and diarrhea did not reoccur. Colonoscopy with biopsy showed a significant improvement in pathology. CONCLUSION: CC in children is rare, and childhood CC induced by a respiratory allergic reaction has not been previously reported. Therefore, this is a special case of CC in a patient who was cured with anti-allergy treatments and desensitization instead of steroid therapy.