Allergic skin disease. 3 Treatment

The corner stone of short-term treatment of allergic skin disease is cortisone: a steroid produced naturally by the adrenal gland, but not in high enough quantities to treat allergies.

This is unlikely to change in the foreseeable future for a number of reasons.

• Cortisone works quickly to make your pet feel better: usually within hours.
• Most pets tolerate cortisone well with few short-term side effects.
• Many other medications such as antihistamines work poorly in dogs & cats.
• Topical treatments (cream & lotions) can be hard to apply.

Please see the separate data sheet on cortisone usage for more information.

Cortisone is usually given orally (tablets) or by injection. Dogs tolerate cortisone in both the short and long term better than people do, and cats tolerate cortisone even better than dogs.

In general short-term cortisone usage does not cause long term side effects. The more cortisone we use in a patient the greater the risk. It is not sensible to try and get cortisone usage to zero in allergic patients, as it is rarely possible without compromising your pet’s quality of life.

Having said that almost everything else we will now talk about, is aimed at minimising cortisone usage

Topical treatments

Topical cortisone (creams, lotions, and sprays) can be useful for small area. They are used most commonly in ears, but can also be useful for feet, and small areas of skin. Only small amounts are absorbed in to the body so the risk of generalized side effects is low. With long term use they can cause dermal atrophy (thinning of the skin).

The main disadvantage is that they are harder to use than tablets, and pets can lick or rub them off.

Shampoos

Bathing can be very useful and works for a number of reasons. Animals with allergies have dry skin. When you wet it, it is soothing but the skin becomes irritated again as soon as the water dries off. Some shampoos form a barrier on the skin to retain the moisture rather like hand cream. It should be noted that the pH of human and dog skin is different. For this reason most human products are very drying to dog skin (and vice versa) so shouldn’t be used.

Dogs with skin disease often develop seborrhoea. This means the skin becomes greasy or flaky, and smells ‘doggy’. Owners often notice the doggy smell return within hours of bathing. Some medicated dog shampoos are sebolytic. In other words they remove this debris from the skin more effectively than normal shampoos, which means that your pet smells better, and is less prone to secondary skin infections.

Shampoos are also available for specific secondary infections that occur in allergic dogs. These include:

• Antibacterial shampoos. Bacterial infection is common on damaged skin. Medicated shampoos can decrease the number of bacteria present, making your dog feel better.
• Malassezia is a greasy yeast infection common in damaged skin. Dogs can develop quite a characteristic odour. Shampoos can significantly improve this condition.

With most medicated shampoos contact time with the skin is important. Most need to be left on for 10 minutes. If you only leave them on for 5 minutes they are half as effective.

Cyclosporin

This is an anti-inflammatory medication that can replace cortisone in some patients. It is often better tolerated than cortisone in some patients and has fewer long-term side effects. Cyclosporin is only useful for dogs with atopy (air-borne allergies) so we need to rule out other causes of allergies before using this medication.

Antihistamines

Antihistamines are occasionally useful for dogs. They are less effective than in people as it appears that histamine does not directly cause itching, as it does in people. It is only the inflammation that comes later that causes distress.

This means antihistamines can be used as a preventative not as a treatment. In dogs with long term problems, you may be able to start antihistamines when their skin is normal, to stop problems recurring so readily. They are not appropriate to treat acute outbreaks of disease. We can discuss with you which antihistamines may be useful for a trial in your pet.

Insect control

Fleabite allergies are common and animals with fleabite allergies will often also react adversely to ant bites. Good quality flea control can greatly aid dogs with this skin problem. If you remember our discussion of thresholds (Allergic skin disease 1: causes & diagnosis, Figure 1), animals which have primarily air borne allergies (atopy) can still have a component of their disease caused by insect bites.

Many highly effective insect treatments are now available. Comfortis tablets are one of the most effective. Topicals, placed on the back of the neck, such as advantage, advocate, revolution, and frontline can also be very effective.