A recent rash (no pun intended) of itching animals prompted me to think about allergies, dermatitis (inflamed skin), and asthma. Skin problems are one of the most common reasons for visits to the veterinarian. In fact, unresolved skin problems sends more people from their primary care veterinarian to another vet for a second opinion than any other reason.
The usual conversation starts like this: "Doctor, please make "Puffy" comfortable. She has a retched itch. "Puffy" has been scratching for a week; rubbing against furniture, losing hair, and no one can sleep because symptoms seem worse at night. I would like her "allergy shot". She gets it every year along with her other shots and she is fine after that."
Typically, the "allergy shot" is an injection of a cortisone-like product. Indeed, corticosteroids are the most powerful anti-itch medication that we have. But.... they are a quick fix and long-term use can cause undesirable side effects including, excessive drinking, urinating, and eating. Hair loss, muscle wasting, and an increased susceptibility to skin and bladder infections are also side effects.
"Well, you don't want to use steroids. What are you going to do?" It is important to find the cause of itching (pruritus). This is often very complex, time consuming, and difficult because so many factors make animals itch. Although itching is caused by mechanical, electrical, hormonal, and thermal factors, it appears that there is a point or imaginary line above which animals scratch and below which they do not. Thus, it is when these factors are added together that itching becomes most intense. The more factors influencing the animal at one time, the more intense the sensitivity and itching.
The list of common causes of itching must start with fleas. Fleas physically irritate skin and flea saliva is a potent stimulator of blood born chemicals that cause itching. However, don't be fooled; fleas aggravate but are rarely the only cause of itching. Allergies to grass and tree pollen, house dust mites, molds, and food (preservatives and components) can be extremely offensive to the immune system. Metabolic diseases such as hypothyroidism also cloud the picture. Then there is "atopy", the inherited predisposition for the body to produce antibodies to inhaled, ingested, and absorbed environmental proteins.
A detailed history of the problem including, inherited factors like breed and family tendencies, age when scratching started, type of food eaten, seasonality of the problem, and presence of other signs is important. Your veterinarian can perform several tests that will determine what your pet is most sensitive to. The more information you have to offer your veterinarian, the greater the likelihood of being able to piece the puzzle together.
Well what about asthma and allergies? Asthma is often diagnosed, yet the causes are poorly understood. We do know that the lower airways in the lungs are hypersensitive and irritated by a group of nonspecific agents (kitty litter dust, smoke, fumes from cleaning products, pollens, molds, dietary components etc.). Exposure causes airways to become inflamed and smooth muscles in the airways contract resulting in an asthma attack. Signs are similar to human asthmatics; coughing and wheezing. We try to control asthmatic attacks with steroids, bronchodilators, and owner education. Antibiotics are effective when asthma is caused by bacteria. We find that anxious, nervous patients are more susceptible to asthma. Minimizing environmental changes and stress in the household helps to reduce the frequency of attacks.
Avoidance is the best policy when it comes to allergies, but your pet can't live in a bubble. Dietary free fatty acid and zinc supplements are a tremendous help to reduce itching in some patients.
In conclusion, if your pet itches, make sure the thyroid gland is functioning normally, control fleas, feed him/her a diet that has as few preservatives as possible (note, I did not say Lamb and Rice), and bathe regularly with specially formulated shampoos.