Erythema Multiforme in Canines

Erythema multiforme is a skin condition that causes raised spots or other skin lesions. It occurs as a reaction to medication, illness or infections. If your dog's sporting a nasty rash, it may be the result of his immune system fighting back against one of those triggers.

Your pup's immune system is always at work, ready to do battle to keep his body healthy. Sometimes his immune system will take particular offense to something and respond in an unusual way. Hunter may have an infection, or he may be taking medicine, such as an anti-inflammatory or antibiotic, that's triggered his immune system's strange reaction. If he has erythema multiforme, his immune system is responding by destroying skin cells or mucous membranes. Other triggers for erythema multiforme include food allergies and tumors, though it's not unusual to not identify the cause of the condition.

If Hunter has erythema multiforme, his skin will show blisters and reddish bumps. Such outbursts can spread and develop into spots, ulcers and red circles with white centers. Hunter's skin is often affected, and his ears, mouth, pads and groin can be afflicted. He may have a fever and feel lethargic, as well as experience a loss in appetite.

When the vet examines Hunter to make a diagnosis, she'll take biopsies to learn how much damage has been done to his skin. Blood tests, urinalysis and a full medical history will help gain insight into what's causing his reaction. Occasionally, radiographs and ultrasound help in the diagnostic process. The vet will look for triggers such as infection, tumor or reactions to medication. If there's no obvious cause for Hunter's outbreak, the vet may suggest trying a hypoallergenic diet to determine whether a food allergy is causing his erythema multiforme. Often the condition is idiopathic, meaning the cause is undetermined.

In many cases, erythema multiforme is self-limiting -- it will clear up on its own in a few weeks. Sometimes a dog doesn't recover on his own and requires help, such as steroids or other immunosuppressive drugs, to put a stop to the destruction of his skin. Even if Hunter's erythema multiforme is self-limiting, you'll still want to know what's behind his outbreak so you can address the root problem. For example, if he takes medication that's prompting the reaction, the vet should change his prescription. Occasionally a dog suffers from a severe case of erythema multiforme, meaning he may have to be on medication for a longer period. In a rare case, a dog may have to be on immunosuppressive drugs for his lifetime.