Allergic rhinitis antihistamines like azelastine antihistamine nasal spray, relief from symptoms is experienced within 15 minutes allowing for a more immediate 'as-needed' approach to dosage. There is not enough evidence of antihistamine efficacy as an add-on therapy with nasal steroids in the management of intermittent or persistent allergic rhinitis in children, so its adverse effects and additional costs must be considered. Ophthalmic antihistamines (such as azelastine in eye drop form and ketotifen) are used for conjunctivitis, while intranasal forms are used mainly for sneezing, rhinorrhea, and nasal pruritus. Antihistamine drugs can have undesirable side-effects, the most notable one being drowsiness in the
Allergic conjunctivitis injury. There are four classes of selectin blocking agents: (i) carbohydrate based inhibitors targeting all P-, E-, and L-selectins, (ii) antihuman selectin antibodies, (iii) a recombinant truncated form of PSGL-1 immunoglobulin fusion protein, and (iv) small-molecule inhibitors of selectins. Most selectin blockers have failed phase II/III clinical trials, or the studies were ceased due to their unfavorable pharmacokinetics or prohibitive cost. Sphingolipids, present in yeast like "Saccharomyces cerevisiae" and plants, have also shown mitigative effects in animal models of gene knockout mice. Allergic conjunctivitis occurs more frequently among those with allergic conditions, with the symptoms having a seasonal correlation. Allergic