2.FOOD ALLERGIES
The next step is to investigate food allergy. Your vet will recommend a trial diet using foods new to your cat. Home cooked diets using a single protein (e.g. meat or fish) and carbohydrate (e.g. rice or potatoes) with water to drink are best. Give the same amount as tinned or half-again as much as dry foods. Hypoallergenic diets are available from your vet if necessary. Other cat-foods contain a variety of ingredients that vary from batch to batch and are not suitable. Trial diets should be fed for six weeks. Cats should not be fed anything else during the trial. Cats that hunt or are fed elsewhere may need to be kept indoors.

Allergic diseases will wax and wane, so an improvement does not necessarily mean the cat has food allergy. A relapse within 1-2 weeks on the original diet confirms a food allergy. Once stable again on the trial diet, introduce ingredients such as beef, lamb, dairy products etc. one at a time to discover which the cat reacts to. These can then be avoided. Alternatively, a commercial hypoallergenic diet can be tried.

3. ATOPY OR ATOPIC DERMATITIS
If skin problems persist then allergy tests should be used to identify what your cat is allergic to - the allergens - for treatment or avoidance. Allergy tests should be carried out by an experienced veterinary dermatologist.
a) Skin testing. Cats are sedated and the fur on the side of the chest clipped. Several dust mite, insect, pollen and mould extracts are injected and any reactions noted. Most reactions occur within 20 minutes although some may take 12-24 hours. Skin tests are very specific, but some cats have negative tests.
b) Serological tests. A blood sample is taken and sent off for laboratory testing. The tests show which allergens are producing antibodies in the blood. Serological tests are not quite as exact as skin tests, and are not necessarily cheaper. They are useful if skin tests fail, or if the cat's skin is in such bad condition that a skin test cannot be run.

TREATMENT
1. Basic Treatment
Thorough flea control is important in all cases of allergic skin disease. Regular worming and a high quality balanced diet will also be of benefit.
2. Lifestyle Management
Some allergens can be avoided. Dust mites and pollens are ubiquitous, but keeping cats out of bedrooms and carpeted rooms, using solid or washable cat-beds, vacuum cleaners with filters and improving ventilation will help.
3. Immunotherapy
Most veterinary dermatologists use immunotherapy to desensitise your cat by giving regular injections of allergens identified by skin or blood tests. Most cats tolerate the injections very well. Your vet will usually administer the first few injections in the unlikely chance of an allergic shock, or anaphylactic, reaction, but most owners give the injections at home thereafter. Mild itching and injection site nodules are minor problems. Approximately two thirds of cases respond to immunotherapy.
4. Anti-inflammatory Treatment
Anti-inflammatory treatment may be necessary if your cat does not respond to immunotherapy. Short-term treatment may be used during flea control or food trials.
a) Antihistamines
Many of these drugs are available from pharmacists, but the doses in cats are different from people, and they should only used under veterinary supervision. Your vet will try 3-4 drugs to select the most effective. Side effects are uncommon, but include sedation and vomiting. Only about 50% of cats respond to antihistamines, although the response is better if they are combined with essential fatty acids.
b) Essential Fatty Acids
These are fish and plant (e.g. Evening Primrose or Borage) oils. Veterinary products are preferred unlike cheaper brands that vary from batch to batch. The initial course is usually eight weeks, although again no more than 50% of cases respond.
c) Steroids
These are cheap and effective, but can have serious side effects (including weight gain, excessive drinking and urinating, infections, diabetes, liver and skin problems) and are generally used as a last resort. Many cats tolerate low doses of steroids given on alternate days quite well. Using other treatments often reduces the dose required. Cats on long-term steroids should have regular check ups.
5. Other Treatment Options
Without controlled studies it is difficult to know if alternative remedies are of any benefit. Many human remedies can be quite toxic in cats and should only be given under veterinary supervision. Female sex hormones (e.g. Ovarid®) have little role in feline dermatology. Serious side effects are common, and these drugs should only be used to treat specific conditions by an experienced veterinary dermatologist.

READERS EXPERIENCES AND THEIR TIPS

STRESS
Fur pulling can be a response to stress. I have some suggestions if this is so but first rule out other possibilities. Cats can be stressed by a change in household routine, new household members, new homes, time in cattery, or trauma from something like spending time at the vet or being locked in a cupboard. Other stresses are high frequency sound, death of a human or animal companion, bullying by fellow cats whether inside or outside the house. Boredom, long periods with little to do, can also produce stress reactions.

PAIN
A reader writes: "Our 14 year old tabby pulled out vast patches of fur and the vet could not discover the cause. There were no signs of fleas. Eventually he proved to be suffering from a tumour on the side of his tongue. He was pulling fur out because it was dirty and he could not reach to clean it with his tongue. In the end he could not even eat. I would urge readers to make sure that the vet examines this possibility."

READERS' EXPERIENCES (continued).

"When the severe hair loss round Flora's hindquarters began nine months ago she was seen by 2 vets, neither of whom found any sign of fleas. Both suspected a hormonal problem and prescribed various things, none of which had any effect. Eventually she was seen by a different vet and a close examination revealed a few bits of debris that could have been from fleas, though no actual fleas. This vet prescribed Frontline spray and a monthly dose of Program for Flora and the dog ­ belt and braces. From that point on recovery was quite dramatic. It all seems to show that even a single flea is enough to trigger the allergy if your cat happens to be highly sensitive". J.B. Godalming

A reader whose cat suffered repeatedly said "an aromatherapy friend suggested a couple of drops of lavender oil on my hand then stroked over the affected part." Unlikely though this seems, TD of Market Harborough has written to say this has helped in the case of the stressed Siamese. Worth trying.

There is a product called Efapet Problem Skin Relief, which diminishes (does not cure) skin allergies. Worth trying on a cat with atopy or one with flea allergy (though it's no good for cats allergic to fish).

A coley steak daily, combined with complete cat food, seems to have helped Douglas, a cat who had this condition, says his owner. Worth trying.
There's a Hair and Skin food from Royal Canin. This claims to be particularly good for hair and skin and might be worth trying. Let me know if you think there's an improvement.

Animal Alternatives 020 8 940 3725 do a skin supplement with omega oils.
Allergy testing. TLC Pet Allergy Testing http://www.animal-allergy.com