One-year evaluation of clinical and immunological efficacy and safety of sublingual versus subcutaneous allergen immunotherapy in allergic conjunctivitis

Background The aim of this study is to evaluate the clinical and immunological efficacy and safety of allergen immunotherapy (AIT) in patients with allergic conjunctivitis (AC) and to compare between sublingual and subcutaneous routes of administration. Methods A prospective comparative case series study was performed on 100 patients with IgE-mediated AC. Patients were referred to allergy clinics for skin prick test (SPT) and AIT. Patients with positive SPT and high-serum IgE level were enrolled in this study. Patients were divided into two groups: sublingual immunotherapy (SLIT) group (50 patients) and subcutaneous immunotherapy (SCIT) group (50 patients). Both groups were followed for 1 year. Efficacy was assessed clinically by comparing pre- and post-treatment symptoms and medication scores and assessed immunologically by comparing pre- and post-treatment serum IgE level and wheal diameter of SPT. Safety of the therapy was assessed by the occurrence of adverse reactions and patient tolerability to the therapy. Results Patients were either mono- or polysensitized to different allergens. Aeroallergens were significantly more common than food allergens (P = 0.00). The most prevalent aeroallergens were pollens (40%) and house dust (30%). At 12-month follow-up, both routes SLIT and SCIT led to a statistically significant clinical and immunological improvement (P < 0.05). This improvement was evident in all follow-up parameters including total ocular symptom score (TOSS), medication score, total serum IgE level, and wheal diameter of skin prick test (SPT). There was no significant difference between the two routes of administration (SLIT & SCIT) in any of the follow-up parameters (P > 0.05). Patients were able to tolerate the allergen therapy without developing any serious adverse events. Conclusion Aeroallergen polysensitization is common among patients with AC. SPT should be included in the diagnostic workup of those patients. AIT is a safe and effective treatment option for patients with AC as it has the potential to achieve significant reduction in symptom and medication scores without ocular or systemic side effects. There is no significant difference between both routes of administration either SLIT or SCIT in achieving clinical and immunologic improvement; so the patient can choose his preferred method for therapy.