Expert: Dr. Louis N. Gotthelf - 11/30/2011

Question
Our 7 month old puppy has now developed her 3rd skin lesion on her head/face area.  They start as hair-covered thickened perfectly circular areas about dime size and then spread in a perfectly circular pattern. One spread to about silver dollar size in about a week.  Once scratched or irritated they lose the hair and become red and inflamed pretty much overnight.  If squeezed pus comes out of them.  They do not appear to be itchy or irritating to her until they get to the inflamed and pus filled stage.  Vet has ruled out mites and round-worm.  1st one cleared up with anti-biotics.  Second one did nothing with anti-biotics so vet started steroids.  Next morning after starting the steroids redness was reduced and now it is dry and light pink in color.  Yeah!  But now I find a third one has developed while on the steroids.  Our vet says he has never seen anything that looked or behaved like they do and he has no idea what they are.  Any ideas?  Nothing strange in her behavior.  Still eating and playing like a 7 month old boxer.  She has been digging under the fence and bringing back dead fish from the neighbors yard.  And she is a white boxer with very pink skin and always rashy somewhere.  They did scrapes and looked under micro-scope and found no bacteria. Only a lot of red and white cells.  Next step is dermatologist or biopsy.  We just lost two boxers (one who just passed under her favorite tree at the age of 10 and one to lymphoma) in the last two years and this was supposed to be our healthy young baby.  So frustrating!!!

Answer
These are probably pustules from a bacterial infection.  The vet can culture a pustule before it ruptures to see.  The puppy may need to stay on antibiotics for 3-4 weeks.  One common reason for this in a pup is a food intolerance or a food allergy.  This type of skin problem does respond to antibiotics and may not respond to steroids. You might ask your vet to tell you about special diets for pups with food allergies.  Of course a skin biopsy will tell the vet the type of disease (allergic,parasitic, hormonal, neoplastic, autoimmune, etc.).