CANINE ATOPIC DERMATITIS

Facts about canine atopic dermatitis (allergic inhalant dermatitis, AID, canine atopy):

• Canine atopic dermatitis is an inherited predisposition to develop allergic symptoms following repeated exposure to inhalant allergens.
• Age of onset of symptoms is usually between six months and three years.
• Due to the hereditary nature of the disease several breeds such as Golden Retrievers, most Terriers, Poodles and Irish Setters have higher incidence.  Many mixed breed dogs are also affected.
• Symptoms may be seasonal or year round.  They tend to become worse and have a longer season as the dog ages.
• Common causes of canine atopic dermatitis include pollens, (trees, weeds, grasses), molds, dust, wool, cat dander, and feathers.

Clinical Signs:

• The primary clinical sign is scratching, most often in one or more of the following areas: under front legs (arm pit area), between back legs, lower abdomen, face (rubbing), and feet (licking).  Other types of allergies may affect the same areas.
• Secondary lesions resulting from the scratching are common including hair loss, redness, seborrhea (scaly skin with bad odor), and hyperpigmentation (dark skin).

Diagnosis:

The only way to identify specific allergens is to skin test the dog.  The dog must no be under the influence of cortisone (steriods).  Waiting time following the oral administration of cortisone may vary from two to four weeks.  There may be up to two months waiting time after a long-acting cortisone injection.  Type of cortisone, frequency of use, and dosage are factors to consider.

Treatment:

Hyposensitization -

• The preferred method of treatment is hyposensitization using allergy vaccine. 
•  An initial series of injections, usually every three days, for six weeks, is injected under the skin.
• Periodic boosters, often every one to four weeks, may be required for life.  If scratching is seasonal, the vaccine may not have to be given all year.
• A common mistake is to discontinue the vaccine when improvement is noted, rather than continuing with boosters.
• A period of several months may be required to see significant improvement.  Approximately 70-75% of the dogs improve with hyposensititization.  In about 25% of theses dogs some cortisone will still be required in doses and frequency less than that required before hyposensitization.
• Cortisone in minimal dosages may be given while hyposensitizing.

Atopica

• Considered a safer alternative to long-term steroids (prednisone).
• Imporvement noted in about 75% of patients.
• Most common side-effect is vomiting/diarrhea which occurs in about 30% of patients.  This side-effect often resolves with persistent use of the medication.
• Must be used long-term.  Not as "as-needed" drug, so often used only for year-round allergy sufferers.

Cortisone

• Cortisone is the only drug which is consistently effective in masking the allergic symptoms.
• It is preferable to administer the cortisone orally on alternate days in the morning to minimize side effects.
• Known common side effects of most cortisone therapy include increased water intake and increased frequency of urination as well as an increased appetite.
• Long-term treatment may cause increased susceptibility to infection, hair loss, thin skin, liver damage, gastrointestinal problems, and muscle weakness.
• They should only be used on a short term basis or as a last resort.

Antihistamines

• Relieve allergic symptoms in 40% of atopic patients.
• May cause drowsiness, but do not cause any long term health problems.
• There are many classes of antihistamines.  Dogs may respond to one but not the other.

EFA Caps

• Relieve allergic symptoms in 10-20% of atopic patients.
• Have no adverse side effects except rarely diarrhea or excess intestinal gas production.
• Cave as their active ingredient Omega 3 fatty acids.