What allergies can cause itchy eyes
Although the full mechanism of mast cell stabilizers is not entirely understood, it is believed that they prevent the degranulation of mast cells and prevent the release of preformed inflammatory mediators, providing relief by preventing both the early and late-phase allergic response. However, these agents own a slow onset of action, requiring up to 14 days to reach maximal efficacy. They are more effective in preventing symptoms and should therefore be used prophylactically. This class may provide an option for patients who do not tolerate other therapies.
Treatment should start 2 to 4 weeks prior to the start of the allergy season. Topical mast cell stabilizers own minimal ocular side effects, with burning and stinging being the most common effects.7,10,15
AC is an inflammatory response resulting from exposure of the ocular conjunctiva to airborne allergens, including pollen, animal dander, and other environmental allergens.7 The term is used to describe a variety of ocular allergies.
Seasonal allergic conjunctivitis (SAC) and perennial allergic conjunctivitis (PAC) are the two most common forms of AC, representing more than 95% of ocular allergies; of the two, SAC is more prevalent.8,9 These are both associated with an immunoglobulin E–mediated hypersensitivity reaction. The more severe chronic forms of AC include vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC), which are both mast cell–mediated allergic conditions.4,10 Despite some common allergy markers, AKC and VKC own clinical and pathophysiologic features that are diverse from PAC and SAC. They happen less frequently but are potentially more severe and sight-threatening, necessitating referral to an eye specialist.11
Signs and symptoms of SAC and PAC are the same, but they differ in the onset and duration of symptoms, and specific allergen to which the patient is sensitive.
Seasonal allergies are triggered by circulating aeroallergens such as tree, grass, and weed pollens. Symptoms will fluctuate throughout the year, commonly causing exacerbations during times of high pollen counts, such as spring and summer, and during windy and dry weather conditions. Patients who own PAC will experience symptoms that persist throughout the year, owing to continuous exposure to perennial allergens commonly including dust mites, animal dander, and feathers.4,10 Numerous patients who own PAC—almost 79%will also experience a seasonal exacerbation.11
Patients will typically present with bilateral eye symptoms, including red, itchy, and watery eyes; pruritus is considered the hallmark symptom.
The itch may be more aggravating in the nasal quadrant of the eye, ranging from mild to severe. The discharge is generally watery but may contain a little quantity of mucus. There may also be some mild chemosis, or conjunctival swelling, associated with AC.
This prominent swelling and mild redness often gives the conjunctiva a pinkish or milky appearance. Lid edema may also sometimes happen. Although symptoms are generally bilateral, the degree of involvement may not always be symmetrical.3,10-12
When evaluating a patient with ocular complaints, it is significant to recognize when a referral is necessary. Some useful questions can assist the pharmacist distinguish AC from other possible causes (Table 1).
If the patient does not complain of itch, a diagnosis of AC is highly unlikely. However, if a patient is complaining about severe itching, this could be indicative of VKC or AKC, which should immediate a referral. Patients who should immediately be referred to a specialist include those who use contact lenses; those who own experienced trauma to the eye; those with any sign of vision changes including the onset of floaters and diplopia; those who experience severe ocular pain and/or sensitivity to light; and those who are also experiencing any systemic symptoms along with their ocular complaints.4,12,13
Severe allergic reaction (anaphylaxis)
In rare cases, an allergy can lead to a severe allergic reaction, called anaphylaxis or anaphylactic shock, which can be life threatening.
This affects the whole body and usually develops within minutes of exposure to something you’re allergic to.
Signs of anaphylaxis include any of the symptoms above, as well as:
Anaphylaxis is a medical emergency that requires immediate treatment.
Read more about anaphylaxis for information about what to do if it occurs.
Sheet final reviewed: 22 November 2018
Next review due: 22 November 2021
The prevalence of allergic disease has increased over the past few decades, with more than 50 million Americans suffering from some type of allergy.1 Ocular allergies are among the most frequently encountered ophthalmic conditions.
The ocular conjunctiva is a mucosal surface that is constantly accessible to airborne allergens. It is also a common site for allergic inflammation. A commonly encountered ocular allergy is allergic conjunctivitis (AC), affecting up to 30% of the general population. In patients who suffer from allergic rhinitis, ocular symptoms are present in up to 70%.2 AC, which peaks in tardy childhood and young adulthood, is also the most prevalent ocular condition encountered by pediatric healthcare providers, affecting approximately 30% of children.2,3 Although extremely common, AC is often overlooked or undertreated, especially in the pediatric population.4 While thought of as just “itchy eyes,” numerous patients who suffer from allergic conjunctivitis may experience a decreased quality of life, with symptoms affecting numerous aspects of their daily activities.5,6
As patients become more engaged in their own healthcare, the pharmacist is increasingly becoming the first healthcare professional encountered, especially when discussing conditions that own nonprescription medications available for treatment or symptom relief.
Pharmacists are the intermediary between the patient and physician, recognizing when symptoms may be indicative of a more serious condition, warranting a referral. Allergic conjunctivitis represents one of those conditions that pharmacists are going to frequently encounter.
Topical Antihistamine/Vasoconstrictor Combination Products
Topical decongestants were the first agents approved for the treatment of AC with the discovery of tetrahydrozoline in the 1950s and the approval of the first agent, naphazoline, in 1971. Today they are still one of the most common OTC agents used in the management of AC in the absence of medical consultation.
Topical decongestants are effective in alleviating hyperemia but own little to no effect on ocular itching. As such, ocular decongestants were paired with topical antihistamines such as pheniramine and antazoline to assist relieve both the itching and redness. Topical antihistamines block histamine receptors, relieving ocular itching. The combination of an antihistamine with a vasoconstrictor has been shown to be more effective than either agent alone. These topical medications are appropriate for short-term (not more than 10 days) or episodic use only. Regular use has been associated with tachyphylaxis and should not be routinely recommended.
Other adverse effects include burning and stinging upon instillation, and mydriasis. In addition, their duration of action is short, requiring frequent istration.4,7,11,15,16
Main allergy symptoms
Common symptoms of an allergic reaction include:
- swollen lips, tongue, eyes or face
- a raised, itchy, red rash (hives)
- sneezing and an itchy, runny or blocked nose (allergic rhinitis)
- itchy, red, watering eyes (conjunctivitis)
- tummy pain, feeling ill, vomiting or diarrhoea
- wheezing, chest tightness, shortness of breath and a cough
- dry, red and cracked skin
The symptoms vary depending on what you’re allergic to and how you come into contact with it.
For example, you may have a runny nose if exposed to pollen, develop a rash if you own a skin allergy, or feel sick if you eat something you’re allergic to.
See your GP if you or your kid might own had an allergic reaction to something. They can assist determine whether the symptoms are caused by an allergy or another condition.
Read more about diagnosing allergies.
When treating patients suffering from SAC and PAC, goals of therapy include avoidance of allergens, reduction in severity and symptoms, and improvement in quality of life.4 Appropriate management should result in immediate relief and control of symptoms.
Based on symptomatology, patients should be treated in a stepwise approach (Table 2).4 Patients should be questioned in order to identify ocular allergens and educated on how to avoid them. Allergen avoidance measures include checking the pollen count and staying inside when it is high, keeping windows closed, turning on the air conditioning, wearing sunglasses outdoors as a barrier to airborne allergens, avoiding eye rubbing, and using air filters. Application of freezing compresses to the eyes 3 to 4 times per day, using hypoallergenic bedding, and bathing/showering before bedtime may also alleviate symptoms of redness and itchiness.
Application of refrigerated artificial tears may also provide relief; artificial tears provide a barrier and assist improve first-line defense by diluting allergens and inflammatory mediators that may be present on the ocular surface.10,14
If nonpharmacologic measures do not offer adequate relief, pharmacologic agents can be utilized. Pharmacologic treatments include the use of topical antihistamine/vasoconstrictor combination products, mast cell stabilizers, antihistamines with mast cell stabilizing properties, nonsteroidal anti-inflammatory agents, and corticosteroids (Table 3).