Feline Allergic Dermatitis
Allergic skin diseases are very common in the domesticated cat. Depending
on the location, characteristics, size and distribution of the lesions,
it may be differentiated as a
These conditions are generally secondary to some type of allergy (flea,
food, drug, insect bites, inhalant (pollen), some underlying disease or
they may result from excessive licking due to boredom in some cats.
Eosinophilic Granuloma (Linear Granuloma)
As stated previously, these conditions are generally secondary to some
type of allergy (flea, food, drug, insect bites, inhalant (pollen), some
underlying disease or they may result from excessive licking due to boredom
in some cats.
Miliary dermatitis is the most common of the allergy reaction patterns
seen in the cat. "Miliary" is merely a term used to describe the small,
raised papules (sores) and crusts (scabs) over the cats head, neck and
back. These lesions come about due to the cat licking and biting at these
areas secondary to itching, This condition gets this name from people saying
it felt as if there were millet grains under the animals skin. It generally
appears in the spring and summer and may get better in the fall and winter
(fewer allergens are present during these times ).
Eosinophilic ulcer - (rodent ulcers, indolent ulcers) - usually
first appear as a small, open sores on the upper lip, just below the nose.
The center of the sore has an ulcerated ("scooped out") appearance. If
untreated, the sore usually increases in size and depth. In severe cases,
the sore may involve the entire upper lip and extend into the mouth. Rodent
ulcers occasionally appear in other areas, such as on the back legs. These
sores are not usually painful and generally occur in female cats averaging
5-6 years of age. Their cause is unknown, but constant licking of the ulcers
probably enlarges them. These ulcers occasionally become cancerous (squamous
cell carcinoma) if left untreated.
Eosinophilic plaques are well-defined, raised sores with concave
surfaces. They occur most commonly on the abdomen or inside thigh of younger
adult cats (females are generally affected more often). The sores itch
intensely, and cats tend to lick them constantly. This condition is often
associated with secondary bacterial infections.
Linear granulomas are narrow, elongated, reddish-yellow sores usually
found on the back of the hind legs in cats 1-5 years old. Hair loss is
generally very minor, and such sores rarely itch. Occasionally linear granulomas
are found on the lips, tongue and hard palate.
Most rodent ulcers respond well to treatment with injectable
anti-inflammatory drugs like DepoMedrol (cortisone). We generally like
to treat with injections every two weeks until the lesion clears. Ulcers
that do not heal fully with drug therapy may require surgical or laser
Miliary dermatitis responds well to the injectable cortisone
(DepoMedrol). This condition may relapse as soon as one month or it may
be several months or even the next year before it returns.
With the eosinophilic plaque and eosinophilic granuloma,
treatment is also geared to using anti-inflammatory medications like DepoMedrol.
Some severe or resistant conditions may respond a little or not at all
to this therapy. For these cases, we may discuss the use of hormone treatments.
The hormone Megestrol acetate, has been used with some success, but it
does have a potential for some very serious side effects. It may cause
weight gain, lethargy, mammary gland tumors, diabetes mellitus and bone
marrow suppression (reduction in the overall number of circulating blood
These conditions are also commonly treated with antibiotics, because
of the secondary bacterial infections associated with them.
Since these conditions are most commonly seen secondarily to some type
of allergic response, removing any potential allergens is highly recommended.
Changing the animals diet to a hypoallergenic food (lamb and rice, turkey
and barley), controlling the flea population (shampoos, Program for your
pet and environmental treatments) may be of great help in certain cases.
Before a diet is considered to not be of help, it must have been feed (exclusively)
for at least 10 (ten) weeks.
Three important points to remember with these conditions are:
Relapses are common, and long-term treatment is often necessary.
Response to treatment is unpredictable.
Some require lifelong treatment.
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