Conjunctivitis%20-%20allergic,%20seasonal%20-and-%20perennial%20(pediatric) Treatment
Pharmacotherapy
Antihistamines (Ophthalmic)
Vasoconstrictors (Ophthalmic)
- Eg Emedastine, Levocabastine, Nedocromil
- Compete for the histamine receptor sites
- In human conjunctiva, stimulation of H1 receptor mediates symptoms of pruritus while H2 receptor is involved in vasodilation
- Reduce itching and vasodilation
- Emedastine was shown to be more effective than Levocabastine in decreasing chemosis, eyelid swelling, and other signs and symptoms of seasonal allergic conjunctivitis
- A selective H1 antagonist with no adrenergic, dopaminergic or serotonergic effect
- Emedastine was shown to be more effective than Levocabastine in decreasing chemosis, eyelid swelling, and other signs and symptoms of seasonal allergic conjunctivitis
- Provides immediate ocular relief as compared to oral antihistamines
- May be used as monotherapy or in combination with decongestants/vasoconstrictors in treating signs and symptoms of allergic conjunctivitis
- Antihistamine with decongestant/vasoconstrictor should not be used for >2 weeks without medical advice
- Should not be used for >6 weeks without medical advice
- Prolonged use of antihistamines that are nonselective may cause ciliary muscle paralysis, mydriasis, and photophobia, especially when used by patients with lighter irides
- May also cause angle-closure glaucoma particularly in patients who are at risk (ie history of narrow-angle glaucoma, patients with narrow angles)
Antihistamines (Oral)
- Eg Cetirizine, Chlorpheniramine, Hydroxyzine, Loratadine
- May be used as adjunctive therapy for moderate to severe allergic conjunctivitis
- Useful in cases accompanied by non-ocular allergies (eg allergic rhinitis)
- Inferior to ophthalmic antihistamines primarily due to 1- to 2- hours delay from systemic administration to delivery to ocular tissues but has longer duration of action
- More likely than topical antihistamines to cause side effects
- May be associated with drying of mucosal membranes and decreased tear production, especially in patients with concomitant dry eye
Antihistamines/Mast Cell Stabilizers (Ophthalmic)
- Eg Alcaftadine, Azelastine, Bepotastine besilate, Epinastine, Ketotifen, Olopatadine
- Have both mast-cell stabilizing and antihistaminic activity
- Binds to H1 and H2 receptors, stabilizes mast cell, and down-regulates inflammatory markers that affects early and late phases of the conjunctival allergic response
- May be used for either acute or chronic diseases
- Relieve acute symptoms (eg ocular itchiness & redness) and prevent recurrence of allergic conjunctivitis
- Fast-acting, effective and generally well tolerated
Corticosteroids (Ophthalmic)
- Used for the treatment of severe and chronic ocular allergy
- Block inflammatory pathways that perpetuate the persistent and chronic forms of ocular allergy
- Used when patient’s symptoms have not responded to other agents
- 1-2 weeks course can be added to antihistamine/mast cell stabilizers if symptoms were not controlled
- Lowest potency and frequency that relieves the patient’s symptoms should be given
- Relieve symptoms fast
- Should only be used for a short period of time (≤2 weeks) and under the guidance of an experienced ophthalmologist
- Chronic use of topical steroids is associated with glaucoma, cataract formation, and corneal/conjunctival infection
- Lowest potency and frequency that relieves patient’s symptoms should be given
Lubricants (Ophthalmic)
- Consist of saline solution combined with wetting and viscosity agents, which is used 2-6 times per day as needed
- Non-preserved formulations are recommended if will be used frequently to prevent allergic reactions secondary to preservatives
- Assist in the removal and dilution of allergens that come in contact with the eye surface
- Do not alter the pathophysiology of the disease but treat co-existing tear deficiency
- Numerous lubricants that differ by class, osmolarity and electrolyte composition are available
- Many ophthalmic lubricants are available. Please see the latest MIMS for specific formulations.
Mast Cell Stabilizers (Ophthalmic)
- Eg Cromoglicic acid, Lodoxamide, Nedocromil, Pemirolast
- Inhibit degranulation of mast cells which limits the release of inflammatory mediators and platelet-activating factor
- Used for prevention of symptoms and for conditions that are recurrent or persistent
- Have slower onset of action as compared to antihistamines
- Effects of Cromoglicic acid are evident 2-5 days after the initiation of the therapy with maximum improvement of ocular symptoms after 15 days
- Requires multiple applications everyday to show effects
- Most useful in the seasonal management of chronic allergic diseases of the eye
- Have slower onset of action as compared to antihistamines
- Usually given to patients with moderate symptoms, after an ophthalmic decongestant have been administered to provide immediate relief
- Studies have shown that Lodoxamide is more effective than Cromoglicic acid in reducing eosinophil activation, and clinical signs and symptoms
- Pemirolast was shown to specifically inhibit mast cell degranulation, preventing the release of chemical mediators like histamine
- May also help in improving symptoms of allergic rhinitis
- Generally well tolerated and may be used as long as needed
Nonsteroidal Anti-inflammatory Drugs (Ophthalmic)
- Eg Ketorolac
- Inhibits the activity of cyclooxygenase blocking the production of prostaglandins
- Helps reduce ocular signs and symptoms like itching or conjunctival hyperemia
- Do not mask ocular infections, affect wound healing or intraocular pressure, nor contribute to cataract formation
Vasoconstrictors (Ophthalmic)
- Eg Naphazoline, Phenylephrine, Tetrahydrozoline
- Sympathomimetic agents
- Decreases vascular congestion and eyelid edema but do not affect allergic response
- Usually used in combination with ophthalmic antihistamines
- Have been shown to have synergistic effect
- Based on studies, Naphazoline plus Antazolin or Pheniramine were comparable in decreasing the signs and symptoms of allergic conjunctivitis
- Have been shown to have synergistic effect
- Chronic use (>10 days) may cause conjunctivitis medicamentosa
Non-Pharmacological Therapy
Identification of Trigger Factors
- Trial of avoidance may identify antigens
- Skin testing or allergen challenge (serum antigen specific IgE antibody measurements) may be useful for identifying specific problematic antigens but are rarely needed
Avoidance of Trigger Factors
- Eg closing windows, filtering air, removing pets and stuffed toys, vacuuming and dusting regularly, etc
- Mainstay of managing allergic conjunctivitis
- Use of goggle-type glasses are recommended during pollen-flying period
- Reduce or avoid use of contact lens during seasonal flare-ups
- House mites are a common allergen and can be reduced by using dust mite-proof encasings on pillows and mattresses, and washing sheets in hot water
- Sensitive patients should attempt to limit exposure to outdoors during times of high pollen count or other allergen counts
Cold Compress
- Causes vasoconstriction which can improve patient comfort by reducing itching
Immunotherapy
Principles of Therapy
- Repeated administration of specific allergens in patients with IgE-mediated conditions to provide protection against allergic symptoms associated with exposure to these allergens
- Only intervention that alters the natural history of allergic rhinoconjunctivitis
- Activates regulatory T cells, thereby altering humoral response to allergens by increasing CD8+ T cells and IL-10, and reducing IL-13 production
- Indicated for patients with the following:
- Evidence of specific IgE antibody to allergen (positive allergy test results)
- Any of the following:
- Clinically diagnosed with both allergic rhinoconjunctivitis & asthma
- Required medications
- Poor response to avoidance measures
- Adverse effects to medications
- Initial dose should be performed in a medical facility by a trained personnel
- Recommended course is usually 4-5 years
Subcutaneous Immunotherapy (SCIT)
- Efficacy is comparable to that of nasal glucocorticoids
- Limited by frequent injection on regular basis and small risk of anaphylactic reactions
Sublingual immunotherapy (SLIT)
- A more viable treatment compared to SCIT as self-administration is encouraged with this form
- Use should be limited to those who can tolerate systemic reactions and its treatment
- Auto/self-injectable Epinephrine should be prescribed to all patients receiving SLIT
- Has been associated with mild oral & GI symptoms & less risk for anaphylaxis compared to SCIT