dermatolgical hair loss?

Question
Dr. Gotthelf,
I have a 6 month old black lab/ chow / unknown mix, her name is Haley.  Recently I noticed some hair loss in circular and oval shaped patterns on her upper chest she has 2 that are of size worth noting, one is approx. 3cm in diameter and the other is around 2 cm in diameter.  She is also having some hair loss under her bottom eyelid.  She has also been shedding more than her normal.  One of the patches has some erythema and the other is completely white, it doesn't look like a fungal infection.  It looks as if there are black dots, (possibly hair follicles?. I recently put  a flea collar on her for the first time (she had previously been receiving advantage topically) because she may have picked up a few fleas, i never saw any on her or any eggs.  Her diet has been good and hasn't changed (she eats purina puppy chow), her bowel habits have been normal also.  She recently went in the ocean for the first time a few weeks ago. Can this be related to the flea collar? the ocean? or can this be some kind of dermatitis? Please help i am worried about her.
          Thank you for your time,
             Jennifer Simonson


Answer
In a 6 month old puppy with hair loss, especially on the facial area, I would think of demodex mange first.,  You should ask your vet to do a skin scraping to look for mange mites.  There are other things that can cause this including ringworm or other fungal infections, food allergy, and trauma.