Seasonal Allergic Conjunctivitis (Hay Fever Conjunctivitis); Perennial Allergic Conjunctivitis

The CMGs are guidelines on the diagnosis and management of a range of common and rare, but important, eye conditions that present with varying frequency in primary and first contact care.

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Type I hypersensitivity reaction to specific airborne allergens.
Conjunctival mast cell degranulation liberates histamine and other inflammatory mediators into the tissues and tear film, causing dilatation of conjunctival vessels (→red eye), increased permeability of blood vessels (→oedema), itch
Seasonal allergic conjunctivitis (hay fever conjunctivitis) (SAC)

  • caused by seasonal allergens, especially grass pollen
  • onset of symptoms associated with seasonal production of allergens, e.g. tree pollen: spring; grasses: early summer; weeds and fungal spores: late summer
  • condition not sight-threatening, but may be damaging to quality of life and associated with a significant economic burden

Perennial allergic conjunctivitis (PAC)

  • caused by non-seasonal allergens such as house dust mite or animal dander
  • symptoms throughout the year; may be seasonal exacerbations
  • less common and usually less severe than seasonal type

Predisposing factors

Atopic disposition (40% of population of which only around half manifest allergic disease)
Personal history of allergic disease (hay fever, asthma, eczema, food or drug allergy)
Family history of allergic disease
Exposure to allergens


Red eye
Itching of eye (main symptom)
Watering of eye
May be associated with sneezing and watery nasal discharge
SAC: symptoms seasonal with climatic variations
PAC: symptoms perennial but variable; seasonal exacerbations may occur


Lids: mild to moderate oedema (peri-orbital oedema in severe cases)
Bulbar and tarsal conjunctiva: chemosis (oedema), hyperaemia and diffuse papillary reaction
Cornea: uninvolved

Differential diagnosis

Vernal or Atopic Keratoconjunctivitis (cornea usually involved)
Other allergic conjunctivitis

Management by optometrist

Practitioners should recognise their limitations and where necessary seek further advice or refer the patient elsewhere

Non pharmacological

Identify allergen(s)
Advise avoidance of allergen(s)
Cool compresses for symptomatic relief
Advise against eye rubbing (causes mechanical mast cell degranulation)
(GRADE*: Level of evidence=low, Strength of recommendation=strong)


Ocular lubricants for symptomatic relief
(GRADE*: Level of evidence=low, Strength of recommendation=strong)

Various topical treatment options are available but there is insufficient evidence to recommend the use of one type of medication over another; however the choice of drug may be determined by compliance, cost, and availability of preservative-free formulation (if required). The twice daily dosing regime of dual-action antihistamines may be beneficial in contact lens wearers and in school-age children.

Systemic antihistamine (e.g. tabs cetirizine or loratadine once daily)

  • effective also for other symptoms of hay fever, e.g. allergic rhinitis

(GRADE*: Level of evidence=high, Strength of recommendation=strong)

Management category

B2: alleviation or palliation; normally no referral
B1: if conventional therapy fails, consider referral to Clinical Immunologist for consideration of sub-lingual or other form of immunotherapy

Possible management by ophthalmologist

(Not normally referred)

Evidence base

*GRADE: Grading of Recommendations Assessment, Development and Evaluation (

Sources of evidence

Bilkhu PS, Wolffsohn JS, Naroo SA, Robertson L, Kennedy R. Effectiveness of nonpharmacologic treatments for acute seasonal allergic conjunctivitis. Ophthalmology 2014;121(1):72-8

Calderon MA, Penagos M, Sheikh A, Canonica GW, Durham SR: Sublingual immunotherapy for allergic conjunctivitis: Cochrane systematic review and meta-analysis. Clin Exp Allergy 2011;41:1263-72

Castillo M, Scott NW, Mustafa MZ, Mustafa MS, Azuara-Blanco A. Topical antihistamines and mast cell stabilisers for treating seasonal and perennial allergic conjunctivitis. Cochrane Database Syst Rev.2015;6:CD009566

del Cuvillo A, Sastre J, Montoro J, Jáuregui I, Dávila I, Ferrer M, Bartra J, Mullol J, Valero A. Allergic Conjunctivitis and H1 Antihistamines. J Investig Allergol Clin Immunol. 2009;19,Suppl.1:11-18


La Rosa M, Lionetti E, Reibaldi M, Russo A, Longo A, Leonardi S, Tomarchio S, Avitabile T, Reibaldi A. Allergic conjunctivitis: a comprehensive review of the literature. Ital J Pediatr. 2013;39:18


Patel DS, Arunakirinathan M, Stuart A, Angunawela R. Allergic eye disease. BMJ. 2017;359:j4706

Pitt AD, Smith AF, Lindsell L, Voon LW, Rose PW, Bron AJ. Economic and quality-of-life impact of seasonal allergic conjunctivitis in Oxfordshire. Ophthalmic Epidemiol. 2004;11/1:17-33


Roberts G, Pfaar O, Akdis CA, Ansotegui IJ, Durham SR, Gerth van Wijk R et al. European Academy of Allergy and Clinical Immunology (EAACI) Guidelines on Allergen Immunotherapy: Allergic Rhinoconjunctivitis. Allergy. 2018;73(4):765-798

Plain language summary

Seasonal Allergic Conjunctivitis (SAC) is the eye component of hay fever and one of the most common eye problems, affecting about one fifth of adults. It is caused when a substance called an allergen reaches the eye surface and sets off an allergic reaction. Allergens are usually airborne. Grass pollen is the most common of these and is at its most concentrated in June and July. The allergic reaction releases histamine into the tears and the surface tissues of the eye, causing redness and swelling of the conjunctiva (the membrane covering the white of the eye), watering and itching. People with SAC often have allergic symptoms affecting the nose, throat and sinuses, and they may have asthma, eczema and food or drug allergy also. SAC can be unpleasant and cause people to lose work or school days, but it does not damage the sight. It can be treated with anti-allergy drops or antihistamines in eye drop form. Antihistamine tablets can also be helpful, and will usually control hay fever also.

Perennial Allergic Conjunctivitis (PAC) is rarer than SAC but produces similar symptoms. The main difference is that it is a reaction to a year-round allergen, such as house dust mite. Its treatment is similar.

Conjunctivitis (Seasonal and Perennial Allergic)
Version 13
Date of search 21.10.18
Date of revision 25.10.18
Date of publication 17.04.19
Date for review 20.10.20
© College of Optometrists

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