There are usually two ways that pet allergies result in extensive discussions within my practice. The first will be when there is a possibility that a family pet is contributing to the severity of a child’s allergy symptoms – most typically this will be rhinitis and asthma but sometimes possibly eczema. The other scenario will be when families who have an allergic child are thinking about getting a pet. As a pet owner myself, I know that this is an enormous commitment and one that cannot be entered into lightly, so understandably parents are very worried that if their child is already allergic or is at risk of developing an allergy, that it might not be the right thing to do even though it may feel like intuitively a good thing to do for so many other reasons.
Pet allergies can usually be considered in the same way that other respiratory allergies are in as much as there is a three-pronged approach to dealing with them. The first is avoidance, and whilst on the one hand this may simply mean not buying a pet in the first place, for those that already have one that is a cause of allergies, it will often mean things like making sure that it stays outside of the bedroom and trying to minimise other excessive contact. For many patients this will be enough especially with dog allergies where the allergen is less light than cat allergen and tends to be less diffusely spread around. The next treatment approach is medication which can be simple things such as saline nasal sprays or over the counter antihistamines, but in some cases if the pet allergen is driving more significant symptoms, it may involve winding up existing steroid treatments for conditions such as asthma or eczema. If these conditions are not well-controlled and there is clear evidence that the pet allergen is contributing to the issue, then this may sometimes require some difficult conversations.
The third approach is desensitisation. Typically, desensitising to cat and dog is a treatment that is only considered to alleviate acute symptoms that develop on contact with other people’s pets and not really a treatment that is designed to facilitate having a pet in your own home, although I have had instances where the treatment has been successful enough to allow this. There are also some exciting new developments, for example pet foods that contain substances that bind to the allergens themselves meaning that the pet produces less allergenic protein in the first place. This is already available from Purina for cat allergies and has shown good evidence of clinical relevant effects. It was interesting to see just how much quicker it was for manufacturers to be able to introduce a novel treatment into pet food compared to the much higher regulatory hurdles required to try and introduce novel treatment approaches into humans.
One of the key conversations I often have to have with families when they are considering getting a pet is having to explain that sometimes the allergy tests are not overly useful. For example, a child who has a small positive skin test to cat or dog may well have meaningless sensitisation (the presence of allergic antibodies in their blood) but not actually be allergic and that these test results can only be interpreted in the context of what has happened when the child has had significant exposure to the animal in question. Likewise, if a child has a negative test to a cat or a dog, whilst it means that it is unlikely that they are allergic at that point, if the child was then to have a cat or a dog introduced into the home environment, there remains the possibility that they will develop allergy to it in the medium term. Children with a history of allergies, are also known as atopic – this is the genetically programmed tendency to develop allergic antibodies to certain stimuli. Cat and dog dander are highly effective at generating this type of immune response and thus introducing a furry animal into the house of an allergic child does represent a real risk that this will create problems further down the road. All of this needs to be considered in the wider context of the child’s other allergic issues and, of course, the family’s approach to managing them.