Irritant contact dermatitis and allergic
contact dermatitis are two different conditions discussed together because they
produce similar reactions. Both are caused by contact with a chemical. In
contact dermatitis, the skin reaction is caused by a direct irritating effect
of the chemical. In allergic contact dermatitis, repeated contact produces skin
sensitization that results in an allergic response from subsequent exposure.
Both types of dermatitis are rare in cats because their haircoat and
their grooming habits protect the
skin from sustained contact with chemicals. This is especially true for
allergic contact dermatitis.
Both irritant and allergic contact dermatitis affect parts of the body where
hair is thin or absent-the feet, chin, nose, abdomen, and groin. These areas
are also the most likely to come in contact with chemicals. Liquid irritants
may affect any part of the body.
Your new cat is coming home from the animal shelter tomorrow. Busily you shop, checking off the items on your list, including cat food, toys, a scratching post and myriad other goodies.
And at the very top of the list are litterbox necessities. You head to the nearest pet supply superstore, and are faced with row after row of “all things litter.” Pastel-colored clumping litter, good old clay litter, some that’s made from pine and some that’s made from newspaper...What to choose, what to choose?...
Contact dermatitis of either type produces red, itchy bumps along with inflammation of the skin. Scaliness
follows, and the hair falls out. Excessive scratching causes skin injury and,
secondarily, infected sores. The rash from allergic contact dermatitis may
spread beyond the contact area.
Chemicals that can cause irritant dermatitis include acids and alkalis,
detergents, solvents, soaps, and petroleum by-products. Substances that can
cause an allergic reaction include flea powders, shampoos (particularly those
containing iodine), poison ivy, poison oak and other plants, fibers (including
wool and synthetics), leather, plastic and rubber food and water dishes, and
dyes in carpets. Neomycin, found in many topical medications, can produce an
allergic reaction, as can other drugs and medications.
Flea collar dermatitis is a reaction to the insecticide in the collar. It
affects the skin around the neck, producing local itching and redness, followed
loss and crust formation. This condition may spread to other areas. In
addition to causing local hypersensitivity, flea collars may cause toxicity
from the absorption of chemicals, especially if there is contact between the
collar and broken skin or open sores. Litter box dermatitis, in which the cat
is allergic to the litter being used or an additive in the litter, affects the
feet, the skin around the tail, and the anus.
Treatment: Consider the area of exposure and try to identify the skin
allergen or chemical causing the problem. Prevent exposure. Topical or oral
corticosteroids or antihistamines, prescribed by your veterinarian, can help to
reduce itching and inflammation. They do not cure the problem. Allergyshots and immune therapy may control the symptoms but
do not cure the problem.
If an irritant substance gets on your cat, bathing immediately may minimize
or even eliminate any symptoms.
WebMD Veterinary Reference from "Cat Owner's Home Veterinary Handbook"