Medication Summary
Allergic conjunctivitis can be treated with a variety of drugs. These include topical antihistamines, mast cell stabilizers, nonsteroidal anti-inflammatory drugs (NSAIDs), and corticosteroids. As always, care must be taken when using topical corticosteroids; pulsed regimen is recommended to minimize adverse reactions.
Antihistamines, Ophthalmic
Class Summary
These agents act by competitive inhibition of histamine at the H1 receptor. They block the effects of endogenously released histamine.
Emedastine difumarate (Emadine)
This agent is a relatively selective H1 receptor antagonist for topical administration. The 0.05% ophthalmic solution contains 0.884 mg/mL of emedastine difumarate.
Epinastine (Elestat)
A direct histamine-1 receptor antagonist, epinastine does not penetrate the blood-brain barrier and therefore should not induce adverse CNS effects. It is indicated for symptoms due to allergic conjunctivitis.
Azelastine ophthalmic
Azelastine, now available as a generic, competes with H1-receptor sites on effector cells and inhibits release of histamine and other mediators involved in the allergic response.
Bepotastine besilate ophthalmic solution (Bepreve)
Bepotastine besilate is a topically active antihistamine that directly antagonizes H1-receptors and inhibits release of histamine from mast cells. It is indicated for itching associated with allergic conjunctivitis.
Alcaftadine ophthalmic (Lastacaft)
An H1-receptor antagonist indicated for prevention of itching associated with allergic conjunctivitis, alcaftadine inhibits histamine release from mast cells, decreases chemotaxis, and inhibits eosinophil activation. It is available as a 0.25% ophthalmic solution.
Cetirizine ophthalmic (Zerviate)
Histamine-1 receptor antagonist; inhibits histamine release from mast cells, decreases chemotaxis, and inhibits eosinophil activation. Indicated for ocular itching associated with allergic conjunctivitis. It is administered twice daily.
Mast Cell Stabilizers
Class Summary
Mast cell stabilizers inhibit the degeneration of sensitized mast cells when exposed to specific antigens by inhibiting the release of mediators from the mast cells. These agents block calcium ions from entering the mast cell. Olopatadine is a relatively selective H1 receptor antagonist and inhibitor of histamine release from mast cells. [7, 8]
Lodoxamide tromethamine (Alomide)
Lodoxamide is a mast cell stabilizer. The active ingredient in this product is 1.78 mg lodoxamide tromethamine.
Olopatadine (Patanol, Pataday, Pazeo)
Olopatadine is a relatively selective H1 receptor antagonist and inhibitor of histamine release from mast cells. The active ingredient of Patanol is 1.11 mg olopatadine hydrochloride; Pataday is 2.22 mg olopatadine hydrochloride.
Ketotifen (Zaditor, Alaway, Thera Tears Allergy, Claritin Eye, Zyrtec Itchy Eye)
Ketotifen is an over-the-counter (OTC) antihistamine eye drop. It is a noncompetitive H1-receptor antagonist and mast cell stabilizer. This agent inhibits release of mediators from cells involved in hypersensitivity reactions.
Nedocromil ophthalmic (Alocril)
Nedocromil interferes with mast cell degranulation, specifically with release of leukotrienes and platelet activating factor.
Corticosteroids
Class Summary
Corticosteroids have both anti-inflammatory (glucocorticoid) and salt retaining (mineralocorticoid) properties. Glucocorticoids have profound and varied metabolic effects. In addition, these agents modify the body's immune response to diverse stimuli.
Loteprednol etabonate (Lotemax, Alrex,Inveltys, Eysuvis)
This agent decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reversing increased capillary permeability. It is a topical ester steroid eye drop that poses a decreased risk of glaucoma when compared with prednisolone acetate. It is available in 0.2%, 0.25%, 0.5%, and 1% concentrations, as well as a gel formulation, a preservative-free ointment preparation, and in combination with tobramycin (Zylet, Bausch & Lomb).
Nonsteroidal Anti-inflammatory Drugs (NSAIDs)
Class Summary
The mechanism of action of NSAIDs is believed to be through inhibition of the cyclooxygenase enzyme that is essential in the biosynthesis of prostaglandins, which results in vasoconstriction, decrease in vascular permeability and leukocytosis, and a decrease on intraocular pressure.
Ketorolac tromethamine (Acular, Acuvail)
A member of the pyrrolo-pyrrole group of NSAIDs, ketorolac inhibits prostaglandin synthesis by decreasing activity of the enzyme cyclooxygenase, which results in decreased formation of prostaglandin precursors; in turn, this results in reduced inflammation. The active ingredient is 0.5% ketorolac tromethamine.
Monoclonal Antibodies
Class Summary
Recombinant DNA-derived humanized immunoglobulin G monoclonal antibodies that bind selectively to human immunoglobulin E on the surface of mast cells and basophils may improve symptoms. Therapy reduces mediator release, responsible for promoting an allergic response.
Omalizumab (Xolair)
This biologic is a monoclonal antibody that is highly specific for the IgE receptor, thus blocking binding of high serum levels of IgE in atopic and asthmatic individuals. Also known as Xolair, it is an antibody that helps decrease allergic responses. Xolair is used to treat moderate to severe asthma that is caused by allergies in adults and children who are aged at least 12 years. It is not a rescue medicine for treating an asthma attack. It has been shown to be effective in patients with atopic keratoconjunctivitis.
Decongestants, Ophthalmic
Class Summary
Stimulates alpha-adrenergic receptor in the arterioles of the conjunctiva, thereby decreasing redness in the eye.
Tetrahydrozoline, ophthalmic (Rohto Arctic, Visine Advanced Relief, Visine Maximum Redness Relief)
The alpha-adrenergic effects of tetrahydrozoline in the arterioles of the conjunctiva may produce vasoconstriction.
Ophthalmic Lubricants
Class Summary
Lubricants act as humectants in the eye. The ideal artificial lubricant should be preservative-free; contain potassium, bicarbonate, and other electrolytes; and have a polymeric system to increase its retention time. Lubricating drops are used to reduce morbidity and to prevent complications. Lubricating ointments prevent complications from dry eyes. Ocular inserts reduce symptoms resulting from moderate to severe dry eye syndromes.
Artificial tears (Altalube, Bion Tears, HypoTears, LiquiTears, Soothe, Systane, Tears Again, Viva-Drops)
Artificial tears are used to increase lubrication of the eye. Nonpreserved artificial tears are recommended for use. Tears should be applied liberally throughout the day, and, if necessary, a lubricating ointment may be used at night.
Tables
Characteristics |
VKC |
AKC |
Age at onset |
Generally presents at a younger age than AKC' first decade |
Second to third decade |
Sex |
Males are affected preferentially. |
No sex predilection |
Seasonal variation |
Typically occurs during spring months |
Generally perennial |
Discharge |
Thick mucoid discharge |
Watery and clear discharge |
Conjunctival scarring |
Moderate incidence of conjunctival scarring |
Higher incidence of conjunctival scarring |
Horner-Trantas dots |
Horner-Trantas dots and shield ulcers are commonly seen. |
Presence of Horner-Trantas dots is rare. |
Corneal neovascularization |
Not present, unless secondary to infectious keratitis |
Deep corneal neovascularization tends to develop |
Presence of eosinophils in conjunctival scraping |
Conjunctival scraping reveals eosinophils to a greater degree in VKC than in AKC |
Presence of eosinophils is less likely |
