AED - Allergy - Week 3 Flashcards
Is type I inflammation immediate or delayed? What about type IV?
Type I is immediate
Type IV is delayed
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
What typically forms with type I inflammation in the eye?
Papillae
What typically forms with type IV inflammation in the eye (3)?
Follicles, papillae, phlyctenules
What are the main causes of type IV inflammation in the eye (4)?
Cosmetics
Drugs
Biological foreign bodies
Autoantigens
What are the main causes of non-immune mediated inflammation in the eye (2)?
Drugs
Chemicals
What typically forms with non-immune mediated inflammation in the eye (3)?
Papillae
List the four kinds of allergic conjunctivitis.
Seasonal/perennial conjunctivitis (hayfever)
Vernal keratoconjunctivitis
Atopic keratoconjunctivitis
Giant papillary conjunctivitis
What is seasonal conjunctivitis often associated with?
Allergic rhinitis
How long do symptoms persist if an individual is allergic to perennial allergen?
All year
What type of imflammation is seasonal conjunctivitis?
Purely type I
What percentage of the population is affected by seasonal conunctivitis?
5-20%
Is seasonal conjunctivitis uni- or bilateral?
Bilateral
Define chemosis.
Conjunctival oedema
List 5 signs of conjunctivitis.
Conjunctival papillae
Hyperaemia
Chemosis
Possible lid oedema
Serous and mucous discharge
Is the cornea affected in seasonal conjunctivitis?
No
List 3 symptoms of seasonal conjunctivitis. Which of these is the hallmark?
Itchy eyes - hallmark
Watery eyes
Associated sneezing
List three differential diagnoses for seasonal conjunctivitis.
Other allergic conjunctivitis
Dry eye related surface disease
Other mechanism of conjunctivitis
What four things must be done to assess a suspected seasonal conjunctivitis?
History
Slit lamp
Fluorescein
Lid eversion
List 5 treatment options for seasonal conjunctivitis.
Allergic avoidance
Topical antihistamine
Oral antihistamine
Cold compresses
Topical steroids
What can chronic use of topical vasoconstrictors result in (2)?
Follicular reactions
Contact dermatitis
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.
List 8 symptoms of vernal keratoconjunctivitis.
Intense burning/itching
Watery eyes
Photophobia
Foreign body sensation
Puffy lids
Mucoid discharge
Blurred vision
Eye rubbing
What is vernal keratoconjunctivitis also known as and why?
Spring catarrh, symptoms may become worse in spring and early summer
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