This info came from the website at https://whitehorsevet.com.au/flea-allergy-dermatitis/
What does Flea Allergy mean?
Even our non allergic dogs experience only minor skin irritation in response to flea bites. Even with the presence of dozens of fleas, there can be very little itching. On the other hand, the flea allergic dog has a severe, itch-producing reaction to flea bites, caused by the fleas saliva.
The symptoms include intense itching, chewing, licking and scratching, causing hair loss and in more severe cases open sores and scabs on skin, allowing a secondary bacterial infection to begin. The most commonly involved area affected is the rump (just in front of the tail).
I HAVE NOT SEEN FLEAS ON MY PET. DOES THAT MEAN THAT NONE ARE PRESENT?
No. When a pet is heavily infested, it is easy to find them. However, if the numbers are small, look for what we call ‘flea dirt’.
Flea dirt is the faecal matter from the flea which contains digested blood. It looks like coarsely ground black pepper and varies from tiny black dots to 1/2mm long tubes. For easy identification, place the matter on a piece of tissue and add one or two drops of water, a red stain will become apparent as the water soaks into the digested blood.
