Objective: Allergic rhinitis is a chronic upper respiratory disease characterized by inflammation of the nose due to the accumulation of inflammatory cells. We aimed to investigate the therapeutic efficacy of capsaicin and/or steroids in reducing the symptoms, proinflammatory cytokine levels, and inflammatory cell infiltrations in an animal model of allergic rhinitis.

Materials and Methods: Thirty-five male Wistar rats were divided into five groups. Following injection and initial intranasal challenge with ovalbumin, rats were treated with intraperitoneal capsaicin (50 mg/kg) and/or steroid (10 mg/kg) injection for seven days. After nasal symptom scorings, all rats were sacrificed under anesthesia, and blood samples and nasal septa were collected for hematologic, biochemical, and histopathologic examinations.

Results: The ovalbumin challenge increased nasal symptom scores, eosinophil and basophil counts, the serum IL-4, IL-5, IL-13 and IL- 33 levels, and histopathologic damage. Capsaicin and/or steroid administration attenuated the allergic rhinitis symptoms. There was a therapeutic effect of capsaicin and the combined use of capsaicin and steroids on experimentally-induced allergic rhinitis as reflected by decreases in allergic inflammation and secretion of cytokines. There was no difference between the CAPS, CAPS-STR, and STR groups in terms of allergic rhinitis symptoms.

Conclusion: Parenteral administration of CAPS alone, and especially the combined use of CAPS and STR, effectively treats allergic rhinitis symptoms in a rat model of allergic rhinitis. Our results show that CAPS alone is not an effective alternative to STR but accelerates the recovery of allergic rhinitis.