AED - Allergy - Week 3 Flashcards by B H

Is type I inflammation immediate or delayed? What about type IV?

Type I is immediate
Type IV is delayed

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What are the main causes of type I inflammation in the eyes (3)? Are drugs a common cause?

Usually pollen, dust mites, and SCLs
Very rarely caused by drugs

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What typically forms with type I inflammation in the eye?

Papillae

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What typically forms with type IV inflammation in the eye (3)?

Follicles, papillae, phlyctenules

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What are the main causes of type IV inflammation in the eye (4)?

Cosmetics
Drugs
Biological foreign bodies
Autoantigens

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What are the main causes of non-immune mediated inflammation in the eye (2)?

Drugs
Chemicals

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What typically forms with non-immune mediated inflammation in the eye (3)?

Papillae

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List the four kinds of allergic conjunctivitis.

Seasonal/perennial conjunctivitis (hayfever)
Vernal keratoconjunctivitis
Atopic keratoconjunctivitis
Giant papillary conjunctivitis

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What is seasonal conjunctivitis often associated with?

Allergic rhinitis

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How long do symptoms persist if an individual is allergic to perennial allergen?

All year

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What type of imflammation is seasonal conjunctivitis?

Purely type I

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What percentage of the population is affected by seasonal conunctivitis?

5-20%

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Is seasonal conjunctivitis uni- or bilateral?

Bilateral

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Define chemosis.

Conjunctival oedema

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List 5 signs of conjunctivitis.

Conjunctival papillae
Hyperaemia
Chemosis
Possible lid oedema
Serous and mucous discharge

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Is the cornea affected in seasonal conjunctivitis?

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List 3 symptoms of seasonal conjunctivitis. Which of these is the hallmark?

Itchy eyes - hallmark
Watery eyes
Associated sneezing

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List three differential diagnoses for seasonal conjunctivitis.

Other allergic conjunctivitis
Dry eye related surface disease
Other mechanism of conjunctivitis

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What four things must be done to assess a suspected seasonal conjunctivitis?

History
Slit lamp
Fluorescein
Lid eversion

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List 5 treatment options for seasonal conjunctivitis.

Allergic avoidance
Topical antihistamine
Oral antihistamine
Cold compresses
Topical steroids

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What can chronic use of topical vasoconstrictors result in (2)?

Follicular reactions
Contact dermatitis

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What is the likely cellular cause if mast cell stabilisers do not work with seasonal conjunctivitis? What action should be taken and how long?

Eosinophilic activity
Use steroids concurrently with mast cell stabiliser/antihistamine for 2 weeks.

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List 8 symptoms of vernal keratoconjunctivitis.

Intense burning/itching
Watery eyes
Photophobia
Foreign body sensation
Puffy lids
Mucoid discharge
Blurred vision
Eye rubbing

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What is vernal keratoconjunctivitis also known as and why?

Spring catarrh, symptoms may become worse in spring and early summer

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What type of inflammation is vernal keratoconjunctivitis? Does it account for all its mechanisms?

Part of the mechanism os type I hypersensitivity

Is vernal keratoconjunctivitis common?

Uncommon

Is keratoconjunctivitis uni- or bilateral? Which gender does it affect more?

Bilateral, males>females

Between what ages does vernal keratoconjunctivitis most commonly manifest? What usually happens and what can it develop into? Is this common or rare?

Between 5 and 25 years, usually runs its course by early adulthood Ocassionally develops into AKC

Define atopy.

Individuals with other allergies

What do most individuals with vernal keratoconjunctivitis have?

Atopy or family history of atopy

Which conjunctival region is most commonly affected by vernal keratoconjunctivitis? What else may it affect andin which race is this more common in? Can these two forms coexist?

Usually affects the superior tarsal conjunctiva May also affect the limal area, more common in African descent Limbal and tarsal forms can coexist

List 5 signs of vernal keratoconjunctivitis.

Conjunctival hymeraemia Chemosis Large palpebral papillae (up to 5mm) Stringy mucous discharge (may sit between papillae) Ptosis

List 4 corneal changes that can occur with vernal keratoconjunctivitis.

Superficial punctate keratitis Shield ulcers Subepithelial scarring Eosinophilic plaques

What happens to the limbus with vernal keratoconjunctivitis (4)? What cells is responsible for one of these?

Limbitis with limbal papillae and Horner-Trantas' dots (eosinophils) Pseudogerontoxon

How does a pseudogerontoxon appear?

Whitish band around the peripheral cornea in an area of previously inflammed limbus. Also called cupid's bow.

List two differential diagnoses for vernal keratoconjunctivitis.

Atopic keratoconjunctivitis Giant papillary conjunctivitis

List the four components to assessing vernal keratoconjunctivitis.

History Slit lamp Fluorescein Lid eversion

Describe the pathophysiology of vernal keratoconjunctivitis (2).

Th2 lymphocytes mediate hypoproduction of IgE via II4. They also mediate differentiation and activation of mast cells and eosinophils.

Explain why venral keratoconjunctivitis may improve with the onset of puberty.

Overexpression of oestrogen and progesterone receptors in the conjunctiva

Hypersensitivity to what 3 things may have a role in vernal keratoconjunctivitis?

Wind Dust Sunlight (UV)

Is there a genetic component to vernal keratoconjunctivitis? Explain.

Probable Reduced levels of tear film histamine has been found

List 5 treatment options for vernal keratoconjunctivitis.

Allergen avoidance Topical mast cell inhibitors Corticosteroids Topical NSAIDs Topical cyclosporin

How can shield ulcer resolution be improved in vernal keratoconjunctivitis?

Referral for superficial keratectomy

How often should vernal keratoconjunctivitis be followed up (3)?

Every 1-3 days with shield ulcers Every few weeks during exacerbations Less frequently between exacerbations

Describe why shield ulcers form.

When superficial punctate keratitis-associated vernal keratoconjunctivitis leads to a break in the corneal epithelium

Describe the mechanical hypothesis for shield ulcer formation in vernal keratoconjunctivitis.

Giant papillae on the upper tarsal conjunctiva are responsible for corneal abrasion

Describe the toxin hypothesis for shield ulcer formation in vernal keratoconjunctivitis. What does this additionally explain?

Eosinophil granules found in the inflammatory debris covering the ulcers is cytotoxic and inhibits would healing. Explains ulcer re-epithelialisation after inflammatory debris is removed.

List 7 symptoms of atopic keratoconjunctivitis.

The same as for vernal keratoconjunctivitis Intense itching/burning Watery eyes Photophobia Foreign body sensation Puffy lids Mucoid discharge Blurred vision

When is the typical onset of atopic keratoconjunctivitis? Is it common?

Early adulthood Uncommon

Is atopic keratoconjunctivitis uni- or bilateral? Which gender does it affect more?

Bilateral, males = females

What are individuals with atopic keratoconjunctivitis more prone to (2)?

Staph. blepharitis and HSV

What three conditions is there an increased incidence of with atopic keratoconjunctivitis? Give a reason, if possible.

Keratoconus and retinal detachment - possibly due to eye rubbing Also higher incidence of anterior subcapsular cataract

What type of inflammation is atopic keratoconjunctivitis?

Part of mechanism is type I hypersensitivity

List 7 signs of atopic keratoconjunctivitis.

Atopic dermatitis Stringy mucous discharge Thickened eyelids, crusty Ptosis Papillary hypertrophy Fibrosis/scarring Limbal cysts or papillae

List 3 changes to the cornea with atopic keratoconjunctivitis.

SPK Shield ulcers Horner-Trantas' dots

List two differentia diagnoses for atopic keratoconjunctivitis.

Vernal keratoconjunctivitis GPC

List 9 components to assessing atopic keratoconjunctivitis.

History Slit lamp Fluorescein Lid eversion Lid margins Lens Corneal topography DFE Skin - referral to an allergist via a GP

List 5 treatment options for atopic keratoconjunctivitis.

Allergen avoidance Topical antihistamines/MCS/NSAIDs Corticosteroids Topical cyclosporin Avoid rubbing eyes

What treatment should be avoided with atopic keratoconjunctivitis? Explain why.

Long term topical steroids due to possible glaucoma, cataracts and increased susceptibility to infection

Distinguish veral and atopic keratoconjunctivitis via the following characteristics: Age of onset Sex Seasonal variation Discharge Conjunctival scarring Eosinophils in conjunctival scraping

Age of onset - atopic occurs much earlier (first decade) than vernal (second/third decade) Sex - vernal affects males more than females, atopic is equal Seasonal variation - vernal occurs in spring months typically, atopic is perennial Discharge - vernal is thick mucoid, atopic is watery/clear Scarring - vernal is moderate incidence of scarring, atopic has higher indicence of scarring Eosinophils - vernal is mmore likely to have eosinophils presnt in scrapings

Is the presence of Horner-Trantas' dots common or rare with atopic keratoconjunctivitis?

Rare

Does corneal neovascularisation occur with vernal keratoconjunctivitis? What about atopic?

Vernal - not present unless secondary to infectious keratitis Atopic - deep neovascularisation tends to develop

List 6 symptoms of giant papillary conjunctivitis.

Redness Burning Itch Foreign body sensation In CL wearers, increased lens aareness and exacerbated symptoms

What is giant papillary conjunctivitis associated with (5)?

Allergy to contact lens, CL deposits, solution preservatives, ocular prostheses, protruding sutures

Describe the four gradings for giant papillary conjunctivitis.

1 - slight conjunctival redness with fine papillae and no symptoms 2 - mild injection, 0.3-0.5mm papillae and mild symptoms 3 - moderate injection, +0.5mm papillae with increased contact lens awareness 4 - severe injection, +0.75mm papillae with lens intolerance

List three differential diagnoses for giant papillary conjunctivitis.

Vernal keratoconjunctivitis, limbic keratoconjunctivitis, and seasonal allergic conjunctivitis

List the 5 components for assessing giant papillary conjunctivitis.

History Slit lamp Fluorescein Lid eversion Inspection of CLs/prosthesis

List 5 treatment options for giant papillary conjunctivitis.

Mast cell stabilisers Topical steroids Advise on CL wear Fit new CLs Removal of sutures

List two examples of autoimmune conjunctivitis.

Cicatricial pemphigoid Stevens-Johnson syndrome

Is cicatricial pemphigoid common or rare?

Rare

What is cicatricial pemphigoid characterised by?

Recurrent sub-epithelial blister of the skin and mucous membranes with a tendency to form scar tissue

What age population does cicatricial pemphigoid affect? What gender?

Affects the elderly, females > males

List four clinical signs of cicatricial pemphigoid.

Conjunctival hyperaemia Sub-conjunctival blisters, ulceration, and scarring Chronic sub-epithelial conjunctival scarring and shrinkage Entropion

List three symptoms of cicatricial pemphigoid.

Burning Watery eyes All features of surface exposure disease

List 4 complications of cicatricial pemphigoid and why they occur.

Dry eye - lacrimal gland scarring and goblet cell desctruction Symblepharon - adhesions between palpebral and bulbar conj. Ankyloblepharon - adhesions at the outer canthus between upper and lower lids Keratopahy - exposure, reduced tears, and lagophthalmos

How is cicatricial pemphigoid managed?

Referral to ophthalmological and immunological specialists

What is Stevens-Johnson syndrom characterised by?

An acute inflammation affecting both skin and mucous membranes

Which gender and age population does Stevens-Johnson syndrome affect more?

Healthy young individuals, male > female

What is the most important cause of Stevens-Johnson syndrome?

Often a hypersensitivity reaction to systemic or topical drugs

In what percentage of Stevens-Johnson syndrome cases is the cause found?

50%

List 6 symptoms of Stevens-Johnson syndrome.

Fever Malaise Sore throat Cough (up to 14 days) Headache Skin lesions developing every 2-3 weeks for 1-2 months

What is an ocular feature of acute phase Stevens-Johnson syndrome?

Papillary conjunctivitis

What is the treatment option for Stevens-Johnson syndrome (2)?

Elimination of the causative agent Refer - hospitalisation is often needed