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Conjunctivitis - allergic - Management
What drug treatments should I prescribe for a person with seasonal or perennial conjunctivitis?

  • Before treating a person with seasonal or perennial allergic conjunctivitis, you must exclude the serious causes of a red eye that can result in permanent visual impairment. For further information, see Diagnosing allergic conjunctivitis.
    • When rapid relief of symptoms is required, prescribe an oral or topical ocular antihistamine, depending on the person's preference and previous response to treatment.
    • When prolonged control of symptoms is required, prescribe an oral antihistamine, topical ocular antihistamine, or a topical ocular mast cell stabilizer, depending on the person's preference and previous response to treatment. Explain that they will need to maintain treatment over the period of time that they are exposed to allergens to maintain control of symptoms.
    • When a topical ocular mast cell stabilizer is prescribed long term, also prescribe an oral antihistamine or topical ocular antihistamine, if:
      • Symptom control is needed in the first few weeks while waiting for the mast cell stabilizer to take effect.
      • Breakthrough symptoms occur.
    • When symptoms persist despite treatment with an antihistamine and a mast cell stabilizer:
      • Reassess the diagnosis.
      • Consider prescribing a different antihistamine or mast cell stabilizer.
      • Refer for specialist assessment, depending on clinical judgement.
    • When symptoms are severe and there is no doubt about the diagnosis, consider prescribing a 3–5 day course of an oral corticosteroid to gain rapid control of symptoms while continuing or initiating other treatment to control ongoing symptoms. Refer to an immunologist if oral corticosteroids are required more than very occasionally.
Clarification / Additional information
  • Factors affecting choice of oral or topical antihistamine for rapid control of symptoms:
    • Topical antihistamines have a more rapid onset of action than oral antihistamines and may be preferred for people with occasional symptoms who require treatment only intermittently.
    • Many people find that oral antihistamines are more convenient to use when an antihistamine is required regularly.
  • Factors affecting choice between antihistamines and mast cell stabilizers for long-term control of symptoms:
    • Oral antihistamines may help to control symptoms of allergic rhinitis, which is commonly associated with seasonal and perennial allergic conjunctivitis.
    • Oral antihistamines are available in once-daily preparations that have a long duration of action, making them convenient to use.
    • Oral antihistamines can cause systemic adverse effects, most commonly sedation.
    • Mast cell stabilizers may take several weeks or months to achieve their maximal effect [Suchecki et al, 2003; Khaw et al, 2004].
  • Oral corticosteroids for severe symptoms:
    • When symptoms and signs of eye redness are severe, a serious cause must be considered and the person referred for same-day assessment if there is any doubt about the diagnosis.
    • Consider the diagnosis of severe seasonal or perennial allergic conjunctivitis only when:
      • The person has a clear history of exposure to an allergen that has previously caused seasonal or perennial allergic conjunctivitis.
      • There are no signs of ciliary injection or loss of visual acuity.
Basis for recommendation
  • Antihistamines and mast cell stabilizers:
    • The recommendations for use of antihistamines are based on:
    • The recommendations for use of topical ocular mast cell stabilizers are based on evidence of their effectiveness in reducing symptoms of seasonal allergic conjunctivitis and is supported by expert opinion [American Academy of Ophthalmology, 2003; Khaw et al, 2004].
    • Good-quality trials are lacking that compare the efficacy of:
      • Different antihistamines against each other.
      • Different mast cell stabilizers against each other.
      • Topical antihistamines against oral antihistamines.
      • Combining mast cell stabilizers and antihistamines against use of a single treatment.
    • Despite the lack of evidence, combining antihistamines and mast cell stabilizers is widely recommended [American Academy of Ophthalmology, 2003; Yanoff and Duker, 2004].
    • The recommendation to consider switching to a different antihistamine if symptoms do not settle with the first-choice antihistamine is pragmatic advice based on:
      • The professional opinion of expert reviewers.
      • Extrapolation of the evidence of individual variability in the response to, and tolerability of, antihistamines in the treatment of urticaria and angioedema [Grattan et al, 2001; Zuberbier et al, 2006].
  • Oral corticosteroids:
    • CKS could find no trial evidence of oral corticosteroid use in managing severe symptoms of allergic conjunctivitis.
    • The recommendation to use oral corticosteroids is based on experience of their use in relieving symptom exacerbation in other conditions, for example, the consensus of an international group of experts concluded that a short course of oral corticosteroid can be helpful in rapidly relieving the symptoms of allergic rhinitis [ARIA, 2001]. Clinical experience confirms this consensus and there is no reason not to believe that they may also have a role in the management of severe symptoms of allergic conjunctivitis.

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