Allergic Rhinitis Treatment Market, By Treatment Type (Immunotherapy (Sub-cutaneous Immunotherapy, Sub-lingual Immunotherapy), Anti-histamines, Decongestants, Leukotriene Receptor Antagonists, Corticosteroids, and Others), By Route of Administration (Oral, Nasal, Intraocular, and Others), By Distribution Channel (Hospital Pharmacies, Retail Pharmacies, and E-commerce), By Geography (North America, Latin America, Europe, Asia Pacific, Middle East & Africa)