Allergic Conjunctivitis

Question 1

Allergic Conjunctivitis

Answer 1

acute care / chronic care
cool compresses
OTC vasoconstrictor/antihistamine combo gtt
Rx antihistamines, dual mechanism Rx, steroid gtt
OTC / Rx antihistamines, antihist/decongestant combo PO “sedating” and “non-sedating“ PO
anticipate allergy season with Rx mast cell stabilizer gtts

Question 2

symptoms

Answer 2

itchy, watery, tearing, red scratchy, FB sens

lids “matted shut in AM” swollen?

Question 3

signs

Answer 3

thin watery discharge redness
AM crusting of lashes from drying of tears, serous secretions palpebral conjunctival papillae
conjunctival injection
conjunctival chemosis?
red and edematous eyelids? no preauricular nodes (PAN)

Question 4

pathophysiology

Answer 4

• an allergic response is a reaction of the body’s immune system to foreign substances known as allergens which the body perceives as a potential threat
• the response can be innate (present from birth and nonspecific in activity) or adaptive (acquired memory of and specificity against the same or closely related foreign agent previously encountered)

Question 5

What does the presence of an allergen on the conjunctiva initiate? (2)

Answer 5

1. the release of“pre-formed”inflammatory mediators such as histamine from mast cells
2. the production of arachidonic acid and its conversion into“newly-formed”mediators such as prostaglandins

Question 6

mast cell degranulation

Answer 6

allergen attracts and binds to IgE then adheres to mast cells causing them to degranulate

Question 7

what do histamine and bradykinin stimulate?

Answer 7

nerve endings (nociceptors)

Question 8

What creates sensation of itching?

Answer 8

histamine and bradykinin

Question 9

What increases vascular permeability and vasodilation?

Answer 9

histamine and bradykinin

Question 10

What does vascular permeability and vasodilation cause?

Answer 10

redness and conjunctival injection

Question 11

What do all cells contain in their cell walls?

Answer 11

phospholipid layer

Question 12

What does threat and disruption signal?

Answer 12

Cells convert phospholipids into arachidonic acid

Question 13

What is arachidonic acid metabolized into?

Answer 13

prostaglandins
thromboxanes
leukotrienes

Question 14

What does an allergen’s presence initiate?

Answer 14

arachidonic cascade within conjunctival epithelial cells and within mast cells as they degranulate

Question 15

What do leukotrienes attract?

Answer 15

WBCs (macrophages)

Question 16

treatment options

Answer 16

decrease symptoms/signs

• topical allergy medications
• oral antihistamines

Question 17

OTC treatment

Answer 17

benadryl (diphenhydramine)

chlor-trimeton (chlorpheniramine)

Question 18

benadryl (dosage and age)

Answer 18

25, 50 mg q4-6h (12y)

Question 19

Chlor-Trimeton (dosage and age)

Answer 19

2,4,6,8, 12 mg q4-12 h [< or = 24 mg/24h] (12 y)

Question 20

Rx

Answer 20

Claritin, Alavert
Clarinex
Allegra
Zyrtec

Question 21

Claritin

Answer 21

loratadine

5mg BID,10mg qD,1mg/ml(>6y); 5mg qD(2-6y)

Question 22

Clarinex

Answer 22

desloratadine

5mg (12y)

Question 23

cool compresses

Answer 23

a. cool compresses STRONGLY indicated for allergy; vasoconstriction reduces
chemosis
b. after success decreasing itch with cool compresses (1-3 days?), patient could
experiment with warm compresses which might reduce chemosis by promoting drainage from vasodilation (may also worsen)

Question 24

reduce serous leakage

Answer 24

a. topical decongestants (can cause rebound hypermia) 7
ii. naphazoline (Naphcon, Albalon, Vasocon, etc.)

b. oral decongestants
i. pseudoephedrine 30,60 mg / 120,240 mg extended-release

c. oral anti-histamine + decongestant
i. loratadine 5mg + pseudoephedrine 120mg (Claritin-D Rx)
ii. chlorpheniramine 4 mg + pseudoephedrine 60 mg

Question 25

topical steroids

Answer 25

generally indicated for severe conditions with symptoms and signs b. provide a quick fix for minor allergies c. prone to overuse by the patient d. prone to over-prescribing by the doctor e. potential danger of masking infection and/or inducing glaucoma

Question 26

Regimen of Treatment (in increasing order of therapeutic efficacy for increasingly severe allergic conjunctivitis)

Answer 26

a. cool compresses as much as needed b. OTC topical vasoconstrictors, ≤QID (can cause rebound hyperemia) c. OTC topical vasoconstrictor/antihistamine combination drops (Naphcon-A, Opcon- A, Vasocon-A, etc.) (can cause rebound hyperemia) i. may work synergistically, responses are idiosyncratic, dosage QID d. topical anti-histamines e. topical dual mechanism (anti-H and MCS) f. topical steroid drops - TID to QID i. use only when urgently indicated ii. short term course only g. oral antihistamines h. oral antihistamine/decongestant combinations, BID to QID (primarily for seasonal rhinitis sufferers with allergic conjunctivitis) i. mast cell stabilizers (MCS) i. anticipate start of allergy season by 3-4 weeks ii. QID regimen iii. for chronic allergies only (not acute attacks) j. avoid allergen(s) whenever known and possible

Question 27

Patient communication

Answer 27

• trying to decrease symptoms • discover / prevent exposure to allergen? • pre-treat seasonal allergies weeks in advance of allergy season [mast cell stabilizers QID or OTC ketotifen (Zaditor) BID or Rx olopatadine (Patanol BID / Pataday qD)