- Itching, redness and conjunctival oedema in both eyes are typical symptoms.
- Acute allergic, seasonal, perennial and atopic conjunctivitis are the most common types of allergic eye inflammation.
- Atopic keratoconjunctivitis is more common in patients with previously diagnosed atopic dermatitis.
- Mast cell stabilizer drops used for a sufficiently long time and antihistamine tablets or drops, as necessary, are often sufficient treatment. Moisturizing drops may also alleviate the symptoms.
- Patients with allergic eye inflammation with severe or prolonged symptoms, as well as those whose diagnosis needs to be specified further, should be referred to an ophthalmologist.
- One in three people are estimated to have some allergic disease, and more than 40% of these have eye symptoms.
- Allergic conjunctivitis is estimated to occur in 20% of the population.
Symptoms and findings
Acute allergic conjunctivitis
- Caused by cat dander, for example
- Symptoms usually occur in both eyes. They develop quickly, as soon as within 30 minutes of exposure, and often subside within 24 hours after exposure.
- Itching, redness and watering of the eyes, photophobia, conjunctival oedema (chemosis)
- Lid swelling and lid eczema
Seasonal allergic conjunctivitis (SAC)
- Symptoms caused by tree or grass pollen, for example, and develop within several days or weeks.
- There is often severe itching
- Redness and watering of the eyes, photophobia, conjunctival oedema (chemosis)
- Sometimes mild eczema on the eyelids
Perennial allergic conjunctivitis (PAC)
- Symptoms often occur throughout the year and are milder than in acute or seasonal inflammation, often caused by indoor allergens, such as dust mites, animal dander or mould
- The symptoms often vary, with intermittent exacerbations and periods of milder symptoms
- Itching, bloodshot conjunctiva, watering, lid oedema
- Often severe itching, which may lead to intensive rubbing of the eyes
- Red eyes, watery discharge, photophobia and foreign body sensation
- Often significant effects on lid skin (thickening, swelling), dermatitis and periocular erythema
Vernal keratoconjunctivitis (VKC)
- Itchy eyes, tearing, foreign body sensation, pain
- Mucous discharge
- Blurred vision
- Giant papillae on the inside of the upper eyelid
- Peak incidence in 7–12-year-old boys
- A rarer form of allergy; refer to an ophthalmologist
Giant papillary conjunctivitis (GPC)
- Inflammatory reaction of the eyelid to the use of hard contact lenses, for example, or other mechanical irritation
- Begins with mild itching or irritation
- Clear discharge, as the condition progresses often mostly in the morning
- Intensive itching as the condition continues
- Enlarged papillae on the inside of the upper eyelid
- At first, about 0.3 mm, and as the disease progresses, up to 1–2 mm
Non-allergic eosinophilic conjunctivitis (NAEC)
- A common but underdiagnosed condition resembling allergic eye inflammation
- Often associated with dry eyes
- Similar to non-allergic eosinophilic rhinitis
- Can be diagnosed from a conjunctival exfoliative sample. In addition, dry eye and allergy tests should be performed.
- Diagnostic criteria of NAEC
- Conjunctivitis lasting for at least one month
- Signs of infection
- No atopic allergy (results of skin prick tests negative, no allergen-specific IgE antibodies in serum)
- Conjunctival cytology gives at least one + for eosinophils (on a scale from + to ++++)
- Allergic conjunctivitis is diagnosed based on typical symptoms and findings (see above) and exposure history.
- Allergy tests support the diagnosis. Microbial samples can be taken to exclude other causes.
- Visual acuity, intraocular pressure, fluorescein staining
- Schirmer’s test for dry eyes
- Allergy tests: skin prick tests, IgE tests
- Microbial samples (bacterial and viral)
Further ophthalmological workup
- Serum IgE tests if these have not already been performed
- Eye challenge test, if desensitization is considered or an occupational disease is suspected
- Conjunctival brush cytology
- Biomicroscopy of the eye
- Dry eyes (Dry eye syndrome)
- Bacterial or viral conjunctivitis (Conjunctivitis)
- Non-allergic blepharitis (Blepharitis)
- Ocular rosacea (Rosacea)
- Toxic conjunctivitis
- Malposition of the eyelid (particularly entropion with eyelashes rubbing against the eye surface) (Entropion and ectropion)
- Lid margin tumour
- Conjunctival tumour
Acute allergic conjunctivitis
- Concomitant effective treatment of allergic rhinitis and asthma is essential.
- Antihistamine tablets
- Topical mast cell stabilizer (cromoglycate or lodoxamide drops) alone or combined with an antihistamine
- In addition, antihistamine drops, as necessary (azelastine, emedastine, levocabastine, ketotifen)
- For severe symptoms, brief treatment with topical glucocorticoid drops prescribed by an ophthalmologist
Seasonal allergic conjunctivitis
- Mast cell stabilizer drops
- It is often useful to start medication one week before the pollen season.
- Antihistamine tablets and, additionally, antihistamine drops, as necessary
- A dual action olopatadine product (histamine antagonist and mast cell inhibitor), as necessary
- If there are disturbing symptoms despite the medication, hyposensitization should be considered (Allergen-specific immunotherapy).
Perennial allergic conjunctivitis
- Mast cell stabilizer drops
- Medication can be used as maintenance therapy for several months, as necessary.
- Short-term treatment with antihistamine drops, as necessary
- As prescribed by an ophthalmologist:
- glucocorticoid drops in the beginning and for short-term use, as necessary
- cyclosporine drops, as necessary
- Avoidance of rubbing the eyes
- Cool compresses
- Frequent use of moisturizing drops
- Antihistamine drops, mast cell stabilizers (see above)
- Glucocorticoid or cyclosporine drops prescribed by an ophthalmologist
- Avoidance of factors causing symptoms, such as wind, salt water, sunshine, rubbing the eyes
- Mast cell inhibitor + antihistamine combination drops (olopatadine x 2 or equivalent)
- Requires treatment and follow-up by an ophthalmologist
- Cyclosporine drops prescribed by an ophthalmologist may be considered; glucocorticoid drops prescribed by an ophthalmologist in the beginning of treatment and for short-term treatment during exacerbations, as necessary
Giant papillary conjunctivitis
- Elimination of mechanical irritation
- A 2–4-week break in wearing contact lenses, careful cleaning of contact lenses, change of contact lens material or curvature and size
- Mast cell stabilizers
- Glucocorticoids prescribed by an ophthalmologist for severe inflammation
- Hyposensitization will not help as the condition is not due to environmental allergens but to mechanical irritation.
Non-allergic eosinophilic conjunctivitis
- Diagnosed disease requires treatment by an ophthalmologist.
- At first, glucocorticoid-antimicrobial eye drops, with the treatment monitored by an ophthalmologist
- Treatment is often continued for a long time using mast cell stabilizer and moisturizing eye drops.
- In addition, short courses of glucocorticoid drops are needed.
- In some cases, cyclosporine drops or tacrolimus products are needed.
- Long-term use of antihistamines should be avoided due to their drying effect.
Criteria for referral
- Acute allergic conjunctivitis can often be treated by a GP. If the symptoms are severe or last more than 3 weeks, examination by an ophthalmologist is indicated.
- Seasonal allergic conjunctivitis: refer to an ophthalmologist if there are disturbing symptoms despite medication.
- Perennial conjunctivitis: examination by an ophthalmologist recommended once or twice a year
- Refer the patient to an ophthalmologist if you suspect:
- vernal keratoconjunctivitis
- giant papillary conjunctivitis
- non-allergic eosinophilic conjunctivitis
- Acute allergic conjunctivitis: follow-up by a GP or an ophthalmologist, as necessary
- Seasonal allergic conjunctivitis: follow-up once a year by a GP or an ophthalmologist, as necessary
- Perennial allergic conjunctivitis: follow-up by an ophthalmologist at least once a year
- Vernal keratoconjunctivitis (rare): in children, follow-up by an ophthalmologist at least 3 times a year
- Giant papillary conjunctivitis: follow-up by an ophthalmologist at least once a year
- Non-allergic eosinophilic conjunctivitis: follow-up by an ophthalmologist at least once a year
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