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štvrtok 22. marca 2012

The Patient's Guide to Ocular Allergies

It's finally spring!  I know this fact is a blessing to me since I hate being cold, but for many Americans the transition into spring means untold suffering.  In my area, allergies are a way of life.  By the second week in March my car was permanently covered in a disgusting yellow dusting and my chair was filled with patient after patient with the first flare up of their seasonal ocular allergies.  How do you know if your irritation and discomfort is an allergic reaction? Let's discuss--
Redness, watering, and swelling of the conjunctiva are classic

SYMPTOMS
Itching. Itching.  And itching.  Your eyes may look red, water or feel dry, or you may experience a foreign body sensation, but itching is universal with allergies.  Contact lenses will feel uncomfortable and my patients complain that their lenses feel "dirty."  Mucus debris will deposit on the lenses and you may get some mucus discharge as well. Children often have a hard time telling you what they are feeling, so watch out for eye rubbing.  

SIGNS
The most classic sign I look for are called papillae: red elevations that form from inflammation of the conjunctiva (the tissue that lines the inner eyelid).  Papillae can be different shape and sizes, but they always mean allergy.  Other major signs of allergy are redness (called hyperemia) and swelling (called chemosis).
Fine papillae have red vascular cores.  Even though they are small, the number of papillae in this photo indicates a severe allergic reaction.  Photo from andrewgasson.co.uk
Large cobblestone papillae are found more often in children who suffer from a severe type of allergy called "vernal conjunctivitis".  Frequent eye rubbing is the first tip off!
TREATMENTS
  • For mild cases, artificial tears may be enough.  Best for temporary relief for mild itching.

  • For moderate cases where papillae are are lot less severe than the two photos above, I like to use anti-histamine/mast cell stabilizer combinations.  There are numerous over the counter drops, but my favorites are Zaditor and Alaway.  Prescription drops are much more effective, with common once daily drops including Pataday and Lastacaft.  They provide relief from itching within 5 minutes of instilling the drop
  • Severe cases where there is substantial swelling, large papillary reaction, and marked discomfort, I like to also use a low strength steroid.  My favorite is Alrex, which can be used safely without risk of an intraocular pressure spike.  On really resistant cases, I have used FML or Lotemax ointment (steroid ointments) that can be applied under the eyelid to reduce swelling.
HOW TO PREVENT YOUR ALLERGIC REACTION FROM GETTING SEVERE
If you have undergone allergy testing or know certain irritants that really set off your symptoms, you can track their arrival in your area at pollen.com .  Plan ahead and start using drops as soon as you know symptoms should be forthcoming.  The drops work best when they have a few days to get into your system.  Mast cells in your body release histamine, which is the culprit behind your allergy reaction.  Any drop with a mast cell stabilizer will prevent this release of histamine, but if you start taking the drop after the histamine is released, the mast cell stabilizer isn't effective!


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