In the last column we learned about Flea Bite Allergy/Dermatitis which causes terrible
discomfort in many animals.  I have been asked just  why the itching can continue for 3 days 
or more after all fleas have been removed. 
  The answer will appear when you understand the simple dynamics of a “flea Bite”. The flea 
like the mosquito injects a substance into the skin so that it can readily feast on the blood of it’s
host. This substance or antigen is what causing the intense stinging and itching from both types of
bites. It takes up to 72 hours [3 days] for the blood circulating in the area to remove all 
traces of the antigen at the site of the bite.
  Since not all bites occur at the same time the period over which the itching reaction occurs
may be prolonged. The final answer is around 72 hours from the last flea bite.
  In some dogs like some people the reaction to the antigen is severe and the constant itching
and scratching will set up a perfect location for a secondary bacterial infection.
  Secondary bacterial infections are very hard to control without continuing antibiotic
therapy. Remember your Mom told you not to scratch! It is easier said than done when the
itching is intense. Telling an animal to stop generally results in a momentary lull in the animals
scratching but it will continue. 
  When an animal has a skin lesion or irritation it will often scratch until it does serious skin
damage. This can happen with parasite bites and other skin abrasions. Dogs have been known
to literally scratch their skin to pieces trying to rid themselves of the itch.
  Removing the fleas, and then treating the environment to remove the sources of more fleas is
a known remedy. Baths in a mild skin soothing shampoo after all fleas have been killed can
aid in the healing of the skin. Bag Balm applied to the areas on the skin and can help the reddened
areas heal.
  Most people will challenge the fact that their animal has fleas. They do not understand what a
flea is or that you don’t have to actually see a flea to know that the animal has fleas. The gritty
black residue on the skins surface is flea manure. When an animal is bathed and is covered
with this black gritty residue the bath water will run red as blood. Often scaring the owner
into thinking that the animal has an injury.
  It is not an injury it is the act of adding the fluid back to the color component of blood. That
being hemoglobin [iron] which the flea excretes as fecal matter.
  Some animals can have literally hundreds of fleas and never scratch very often. Others whose
systems are more sensitive can react to just one stray flea. These animal are the ones at
risk of having intense reactions with severe itching and scratching and the accompanying
side effects and secondary bacterial infections.  Strict flea control methods must be employed
to keep these animals flea free.