The Big Itch: Understanding and Managing Ocular and Systemic Allergies
Kelly Kinney Nichols, OD, MPH, PhD
Associate Professor
The Ohio State University College of Optometry
338 W. 10th Ave.
Columbus, OH 43210
(614) 688-5381
nichols.214@osu.edu
Overview:
This lecture will review current topical and systemic medications for allergies, including the
newly released Elistat topical drop for allergic conjunctivitis. Billing, coding and advice for your
patients from a “whole body” approach will be reviewed.
Course objectives:
Following the completion of this course the participant will be able to:
1. Identify common factors associated with ocular and systemic allergy, and
2. Effectively select appropriate management tools for patients with ocular and systemic
allergy.
I. Overview of allergy
A. Prevalence
 An estimated 20% of the general population (over 50 million people in the
U.S.) suffer from allergic conjunctivitis.
 Most people develop allergies in childhood.
 A 2nd group develops post-pubescent allergies (peak incidence of 18 to 35
years of age).
B. Causes of Allergic Reactions
 Environmental
 Genetic
 Medications & Cosmetics
 Devices (contact lenses, sutures)
C. Components of the Allergic Reaction
 Allergic Response
 Mast Cells
a) Mast Cell Degranulation
• Acute phase: (Seasonal Allergic Conjunctivitis)
• upon exposure;
• produced by preformed mediators;
• lasts 1-2 hours;
• manifested in signs and symptoms.
• Late Phase: (Vernal Conjunctivitis)
• 6 to 24 hours after exposure;
• produced by newly formed mediators and inflammatory cells;
• causes tissue damage;
• manifested in cellular response.
Nichols, KK. The Big Itch: Understanding and Managing Ocular and Systemic Allergy
D. Profile of Products Released from Activated Mast Cells
 Histamine
 Others
a) Pre-formed
b) Newly formed
 Eosinophils
E. Specific Allergic Disorders
 Allergic Conjunctivitis
 Atopic Keratoconjunctivitis (AKC)
 Vernal Keratoconjunctivitis (VKC)
 Giant Papillary Conjunctivitis (GPC)
F. Differential Diagnoses of Other External Diseases
 Dry Eye
 Blepharitis
 Viral
 Contact Dermatitis
 Chlamydial
 Pemphigoid
 Bacterial
 Contact lens related (irritant conjunctivitis, infiltrates)
 Ocular Rosacea
 Medicamentosa
G. Non Rx Treatments - Ocular Allergy Management
 Tear Substitutes:
 Cold Compress
 Avoidance of Allergic Source
H. Rx Treatments - Ocular Allergy Management
 Antihistamines
 Mast Cell Stabilizers
 Antihistamine and Mast Cell Stabilizers
 Antihistamine/Vasoconstrictor Combination
 Steroids
 NSAIDs
I. Treatment Options
 Potent H1 Antihistamines
a) Competitively and reversibly block histamine H1 receptors
b) H1 Antihistamines relieve itch
c) Leave other pro-inflammatory mediators, such as prostaglandins and
leukotrienes, uninhibited
d) Provide short term, symptomatic relief
(1) Livostin™ (levocabastine hydrochloride 0.05%)
(2) Emadine™ (emedastine difumarate 0.05%)
(3) Optivar™ (azelastine hydrochloride 0.05%)
Nichols, KK. The Big Itch: Understanding and Managing Ocular and Systemic Allergy
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Mast Cell Stabilizers
a) Exact mechanism of action unclear:
(1) May inhibit Ca++ influx into the cell;
(2) May affect membrane fluidity;
(3) May inhibit phosphorylation of necessary proteins.
(4) Prevent mast cell degranulation:
(5) Prevent histamine release
(6) Inhibits eosinophil chemotactic factor (ECF) release
(7) Prevent the release of pre-formed mediators
(8) Prevent the production of newly formed mediators
(9) Do not relieve existing symptoms
(a) Alocril™ (nedocromil sodium 2%)
(b) Alamast™ (pemirolast potassium 0.1%)
(c) Alomide® (lodoxamide tromethamine 0.1%)
(d) Crolom® (cromolyn sodium 4%)
(e) Opticrom® (cromolyn sodium 4%)
Mast Cell Stabilizer/ Antihistamines
a) Patanol® (olopatadine hydrochloride 0.1%)
b) Zaditor™ (ketotifen fumarate 0.025%)
c) Optivar™ (azelastine HCl 0.05%)
d) Elestat™ (epinastine HCl 0.05%)
(1) Elestat mechanism of action
(2) Elestat vs Patenol
Vasoconstrictors
a) Reduce injection
b) Sympathomimetic adrenergic agents
c) Can induce pupillary dilation at low concentrations
d) The conjunctiva may not experience rebound
(1) Naphazoline, phenylephrine, oxymetazoline, tetrahydrazoline
Antihistamine/Vasoconstrictor Combination
a) Combine H1 receptor antagonists with alpha-adrenergic agonists
b) Block the effects of histamine hence, effective against itching
c) Produce vasoconstriction reducing redness regardless of causative
pathway (alpha-adrenergic effects)
(1) Naphcon-A®, Opcon-A®, Ocuhist® (naphazoline/
pheniramine)
Corticosteroids
a) Cross cell membrane and bind to receptor in cytosol
b) Steroid-receptor complex is transported to nucleus where it affects
protein production
c) Particularly inhibits cytokine, adhesion molecule formation
d) Side Effects: delayed wound healing, secondary infection, elevated
intraocular pressure, cataract formation
e) Treatment should be monitored by an eye care professional
(1) Alrex™ (loteprednol etabonate 0.2%)
NSAIDs
a) Inhibits cyclooxygenase metabolic pathway, stopping production of
prostaglandins (PGs) and thromboxane (Tx)
Nichols, KK. The Big Itch: Understanding and Managing Ocular and Systemic Allergy
b) Does not affect preformed mediators or the lipoxygenase pathway
(leukotrienes, LTs)
c) Hypothesis: PGs synergistic with histamine - potentiating itch
d) Can delay corneal healing by interfering with wound repair
(1) Acular® (ketorolac tromethamine 0.5%)
(2) Acular LS® (ketorolac tromethamine 0.4%)
J. Systemic Medications
 Concurrent conjunctivitis and allergic rhinitis/ sinusitis
 Eyelid myokymia
 Systemic Antihistamines
a) OTC
(1) Benadryl® (diphenhydramine)
(2) Chlor-trimeton® (chlorpheniramine)
(3) Claritin® (loratadine)*, Claritin D*, Claritin D 24H*
b) Rx
(1) Allegra®* (fexofenadine), Allegra D*
(2) Zyrtec® (cetirizine)*, Zyrtec D*
(3) Clarinex®* (desloratadine), Clarinex Reditabs*
c) Nasal corticosteroid spray
(1) Flonase® (fluticasone propionate)
(2) Nasonex® (mometasone furoate monohydrate)
(3) Nasacort AQ® (triamcinolone)
(4) Rhinocort Aqua® (budesonide)
*Optometric prescriptive authority in Ohio
K. Treatment Needs
 Treatment of the disease, not just its symptoms
 Therapies with more favorable side effect profiles than corticosteroids:
systemic antihistamines, vasoconstrictors, and other antihistamine/mast cell
stabilizers
 Broader mechanism of action to block additional mediators as well as
histamine
 Longer duration of action than current mast cell stabilizers: antihistamines or
antihistamine / vasoconstrictor combinations, NSAIDs
 Safe for pediatric use
 Extremely comfortable to ensure patient satisfaction and compliance