D3.57 - Respiratory Manifestations Of Ascariasis Mimicking Allergic Disease: A Clinical Case

Ascariasis is one of the most common helminthiasis infections worldwide, caused by the roundworm Ascaris lumbricoides. The clinical presentation of ascariasis can mimic allergic pathology due to both mechanical tissue damage during the larval migration phase and the induction of a T2 immune response and sensitization of the body by parasite metabolic products.

Case Report: A boy, 3 y and 9 mo old, presented with complaints of a prolonged, unproductive cough in Sept 2024. His medical history revealed that at the ages of 2.5 years (May 2023) and 3.5 years (May 2024), the child also experienced prolonged, unproductive coughs without fever, the latter episode coinciding with the arrival of a dog in the home. At his place of residence, both episodes were diagnosed as pneumonia, and the child received two courses of antibiotic therapy (chest X-rays were not provided by the parents). In September 2024, shortly after starting kindergarten, the child developed similar complaints, which were suspected the onset of bronchial asthma in a child with a history of episodes of bronchial obstruction due to spring pollen. Inhalation therapy (ipratropium bromide + fenoterol, budesonide) was prescribed for 3 w, without a positive effect. The child has no family history of atopy, and the parents deny any history of drug or other allergies. According to the examination, the child's condition is satisfactory, the child is active, the skin is clear, nasal breathing is not obstructed, puerile breathing in the lungs, and wheezing is absent. According to the examination, blood eosinophilia (0.54 * 10⁹ / L), elevated levels of eosinophil cationic protein (52 μg / L) and total IgE (1281 IU / ml), however, specific IgE (ImmunoCap) was not detected. Based on the ineffectiveness of a trial inhalation therapy, the lack of significant sensitization, and elevated total IgE and blood eosinophil levels, a parasitic infestation was suspected. Serological testing revealed IgG antibodies to roundworms (Ascaris lumbricoides), and microscopic examination of stool revealed roundworm eggs. The diagnosis was ascariasis complicated by toxic-allergic syndrome with respiratory tract involvement. The child was prescribed mebendazole 100 mg twice daily for 3 d; the cough completely resolved with anthelmintic therapy. A follow-up examination one month later revealed no roundworm eggs in the stool.

Conclusion: This clinical case demonstrates the importance of excluding helminthiasis in the differential diagnosis of patients with allergic-like symptoms. Routine screening for ascariasis in children with suspected allergic disease is not recommended; however, the examination may be recommended for patients with resistance to standard therapy, detection of eosinophilia and the absence of causative sensitization.