Ischemic Dermatopathy

Before

After

This young Chihuahua, weighing only 1.7 pounds, was presented for progressive crusting and ulceration of the ears of several months duration.  The lesions were first noticed about 3 months following a rabies vaccination.  An area of hair loss and scarring had also occurred over the shoulders at the site of the vaccination.  Biopsy of this lesion revealed remnants of the vaccine and impaired circulation to the skin (ischemia).  Small dogs are predisposed to developing a vascular reaction to some vaccines, probably because they receive the same amount of vaccine as a 100# dog.  Inflammation of the tiny blood vessels in the ears impairs circulation to the edge of the ear in a wedge-shaped pattern, as seen in the picture above.  If the inflammation is allowed to continue, the tissue dies and leaves a permanent defect.  This dog responded well to prednisone and Trental, which suppressed the inflammation and improved the circulation.  Early referral for diagnosis and treatment are important to minimize ear deformity.