Eye diseases
and allergies

Allergies are often mentioned in cases of functional disorders or illnesses of unknown origin. It is sensible and necessary to investigate this suspicion; conversely, not every illness with an unclear cause can be traced back to an allergy.
Understanding cause and effect is a never-ending process in medicine too. The desire for clear statements is understandable but not always possible.

In the case of allergies, the body reacts to recurring external influences, such as pollen or medication, such as preservatives in eye drops. When there is first contact with a so-called allergen (a substance that triggers an allergy), certain antibodies are formed, which cause more or less severe reactions on subsequent contact. These can be redness, swelling and itching to varying degrees.

In the eye, it could be that the conjunctiva and the skin in the eye area, which are in contact with the outside world, are the most likely to react. It must be assumed that both eyes are affected in the case of allergies. Swelling and reddening of the conjunctiva on both sides, as well as itching, are possible. There may also be superficial chafing on both sides of the skin with weeping areas. Such findings are rarely found in horses, whereas the examples mentioned above occur frequently in comparison. Allergies in the eye area are therefore rare.

If an allergic reaction is suspected, it is advisable to carry out a test. Blood tests are very unreliable in this case. Skin tests (intracutaneous tests) with subsequent therapy attempts (hypo- or desensitization) are useful. In my practice, if you suspect an allergic reaction, I recommend attending the skin days at the LMU Munich, which are held in collaboration with the small animal dermatology department. Intracutaneous tests and therapy attempts are carried out here.

Do not give antiallergic eye drops on suspicion.

As a rule, this will not have any effect; it will only prolong the illness. If, after a detailed examination, there is a suspicion of an allergy, I recommend intracutaneous tests followed by an individual desensitization attempt. In each individual case, it must be considered whether a sample of the conjunctiva should be taken before or after referral to a skin specialist.