AISD results from a disorder of the immune system in which the animal’s body sees its own skin as foreign. Because of this abnormal immune response, the skin is damaged.
In a sense, the animal is trying to reject its skin, just as it would try to reject a viral or bacterial infection. Various explanations have been proposed for this disorder including genetic, environmental, drug and viral factors. In dogs, there is some evidence of a genetic component, as AISD is seen more commonly in certain breeds (Akitas, collies, shelties, chows, Dobermans).
Most cases of AISD occur in mature animals with skin lesions first appearing as small red spots that rapidly form a blister, then a pustule or pimple, and finally a crust. In most cases, the major lesions noted by the owner are red spots, ulcers and thick crusts (scabs) that form over the spots. The crusts usually start on the nose, around the eyes and on the earflaps but may also involve the footpads, mouth, anus and genitals. Itchiness is variable. Other signs commonly noted are depression, lethargy, anorexia, lameness, enlarged lymph nodes and fever.
The definitive diagnosis of AISD should always be made prior to treatment as numerous other diseases can look like AISD. Several tests are necessary to diagnose AISD. Blood tests along with cultures and skin biopsies are needed to diagnose if AISD is present, and if so, what type. Sometimes, due to the waxing and waning nature of the AISD, the initial biopsy results are negative making it necessary to perform more biopsies at a later time.
Once the diagnosis has been made, treatment involves using different immunosuppressive medications, all of which are very potent agents and can cause serious side effects with chronic use. A baseline blood panel will be done initially and periodically during treatment to monitor for adverse drug effects.
In most cases, pets with AISD can be controlled with only rare flare-ups, but they must be treated for life. Some cases cannot be controlled. Currently, there is no test to determine which dogs will respond to treatment and which ones will not. It may be necessary to try several different drugs or combinations of drugs before determining whether or not your pet’s disease is controllable.