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.
Prevalence
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
Atopic keratoconjunctivitis
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 ++++)
Workup
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.
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
Antihistamines
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
Follow-up
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