Strongyloides Hyperinfection Treated with Subcutaneous Ivermectin in a Patient with an Inborn Error of Immunity.

Strongyloides hyperinfection can be challenging to diagnose and treat. Although it is typically described in cases of secondary immunodeficiency, it has not previously been reported in a case of inborn error of immunity. Diagnosis via microscopy can be time-consuming and challenging, and serology results may be negative in the setting of hypogammaglobulinemia. Oral ivermectin is an effective treatment for strongyloidiasis and is commonly used in low-endemicity countries. However, its efficacy is limited in cases of malabsorption. Subcutaneous administration of ivermectin is widespread in veterinary medicine, but it is not licensed for use in humans. The use of subcutaneous ivermectin in the treatment of Strongyloides hyperinfection is described in a man with hypogammaglobulinemia secondary to common variable immune deficiency and associated severe malnutrition in the context of chronic Strongyloides-related malabsorption. The diagnostic challenges in low-endemicity settings and therapeutic considerations when oral therapy is unsuccessful are also discussed.