Ellie Masters asked:
My cat is scratching above his eyes and losing fur, sometimes his eyes water too. this happened earlier in the summer he went through testing nothing found, he’s treated with stronghold so no fleas etc. All help appreciated as at wits end now
Hi again Ellie, thanks for your question!
To answer it, I’m going to discuss the possible causes, then the investigations available to demonstrate them, and then finally possible treatment options.
What possible causes are there?
Given that he’s scratching the area around his eyes, losing fur and has watery eyes, there are three immediate possibilities that spring to mind.
The first is a primary eye disease – conjunctivitis, a corneal ulcer, chlamydia or calicivirus infection are probably the four conditions I’d be wanting to rule out. In this situation, the hair loss is because of his constant rubbing at his sore eyes.
The second possibility is that it is a skin disease, manifesting most dramatically on his head above his eyes. This may sound unlikely, but many cats suffer from a condition called miliary dermatitis, where the skin becomes very itchy and forms tiny red scabs or bumps – often it is focussed above the eyes and in front of the ears, although along the back is also a possibility. This is not a diagnosis, but a symptom – and is most commonly associated with parasites, allergies, or skin infections.
The third option is a condition that affects both the skin and the eyes – classically, this would be a more general allergy of some sort. Allergies in cats are less well understood than in dogs, however, food allergies are thought to be the second most common cause of itching in cats (after fleas and other parasites). Other possibilities would include auto-immune disease, where the immune system starts attacking healthy tissues.
So, how do you tell which it is?
If the condition is a primary eye disease, the skin will appear basically normal (although it may be a little reddened or bald due to rubbing, it will not be itchy itself, and the affected areas will ONLY be around the eyes, there won’t be any symptoms anywhere else).
In miliary dermatitis, the tiny (1-3mm across) scabs or bumps will be obvious in the skin – typically above the eyes, in front of the ears, sometimes on the sides or bottom of the neck, and often along the back as well. In fact, it has been called “lumpy cat disease”!
Of course, if both systems are affected, then both sets of symptoms will be apparent.
What could have caused it?
Primary eye diseases are commonly associated with trauma (typically, fighting with other cats, but running through vegetation is also a possibility) or cat-flu infections. Other options include uveitis (inflammation inside the eye) or a displaced lens. I’m not going to talk in much detail about these, because from what you’ve said, it doesn’t sound like this is a specifically eye-related problem.
Itchy skin diseases, however, are fairly common in cats. By far the most common is parasitic dermatitis, caused by ectoparasites (those that live on the surface of the animal) such as fleas, mites (e.g. Notoedres cati, the Cat Scabies Mite) and lice. This is relatively unlikely in your case, because it appears that you use a very effective anti-parasitic, selamectin (Stronghold); if used monthly, in most cats this is very effective at killing fleas and mites, although less good for lice.
I say usually effective, because sometimes, for some reason, we do find that cats get flea problems despite appropriate treatment; this may be because there is a massive environmental reservoir of pupae and larvae (or even adults on other cats or animals) so killing the adults doesn’t resolve the problem; or it may be because the cat is so severely allergic to them that a single bite causes generalised skin disease – even though the biting flea dies within hours, the symptoms may persist for days afterwards.
You can, however, check for fleas and lice easily at home. Fleas are rarely seen live unless in very severe infestations, but their droppings appear as black sand in the coat and when wetted turn bright red (because they are digested blood – this is called the Wet Paper Test). Lice are small insects that are visible with the naked eye, and often you can see the eggs or “nits” adhering to the hair. Mites, on the other hand, can only be ruled out by your vet, by doing skin scrapes and examining them under the microscope. At the same time, they will check for skin infections – bacteria, yeasts, and even ringworm (another fungus) may all cause skin symptoms.
Assuming that you have ruled out these parasites and infections, the next most likely problem is an allergy – reportedly, food allergies are the most common in cats after flea allergies. In cats (and indeed dogs), food allergies do not usually have intestinal symptoms, but instead cause itchy skin disease – and can be a response to any component of the diet (for example, an outdoor cat can become allergic to mice!). Unfortunately, they are very difficult to diagnose – the mechanisms are poorly understood and allergy blood tests are highly unreliable for food reactions. The only way to diagnose the condition in a cat is to perform a Dietary Exclusion and Challenge Trial. This involves:
- Put the cat on a diet containing only protein and carbohydrate sources they have never eaten before – this is rarely possible in practice (!), so usually a commercial hydrolysed hypoallergenic diet is prescribed by the vet, which has been specially formulated and processed so that none of the potentially allergenic molecules is big enough to be recognised by the immune system.
- They must stay on this diet, and this diet only (no treats, snacks or other foods) for 8-13 weeks. If the symptoms do not resolve, then the cat doesn’t have a food allergy. If they do resolve, then either they have a food allergy, or they have another disease which has spontaneously improved (which many allergic conditions do).
- If the symptoms resolved, then you move to the Challenge part of the test, which is to return to the original diet. If there is no change, the cat probably doesn’t have a food allergy; but if the symptoms recur within 10 days, then the condition is a food allergy to one component in the original diet, so they should go back onto the hypoallergenic food.
- You then have the choice of either reintroducing components of the original diet one at a time to try and find out exactly what they’re reacting to, or just stick with the diet that prevents the symptoms – the vast majority of owners (quite sensibly in my opinion) stick with what works!
If parasites, infections and food allergies have been ruled out, there are two possibilities remaining. The first is an environmental allergy – an allergic reaction to something around the cat, such as pollen, dust, dust mites etc etc. Fortunately, there are blood tests available that can help diagnose these conditions – you should discuss them with your vet. Unfortunately, many cats don’t respond very well to antihistamines so these drugs are often of limited use in managing allergies. Allergen avoidance (keeping the cat away from the substance, or vice versa) is therefore the mainstay of treatment, although sometimes medication (e.g. steroids) is used as well.
The final possibility is atopic dermatitis. This condition has been well recognised in dogs for many years, but we now know that cats can suffer from it as well (although it is probably rarer than in dogs). This is a genetic condition that makes the cat abnormally prone to developing allergies, often to a wide range of different harmless substances simultaneously. Although allergen-avoidance (keeping the cat away from the substances they are allergic to) is the ideal, it is often not possible, and in the vast majority of cases, medication to reduce the over-reaction of the immune system is needed (typically cyclosporine and/or steroids).
So where do I go from here?
The key to working out what’s causing any skin condition is to work with your vet and work it up logically:
- Rule out parasites – with wet paper tests, visual examination and skin scrapes. Sometimes, trying a different flea treatment makes a dramatic difference (although from what you’ve said I doubt this is your issue).
- Rule out skin infection – using tape strips, skin swabs and culture (bacterial and possibly fungal).
- Rule out a food allergy with an Exclusion and Challenge Trial
- Test for other allergies.
- If all the above are negative, further tests are needed for more exotic conditions such as feline leprosy or mast cell tumours – however, these are pretty rare!
All the best with him, and I hope you can get to the bottom of the problem!
David Harris BVSc MRCVS