I use Pycnogenol from Da Vinci Labs. In place of using serum injections of the antigens, homeopathy can be used with excellent results. The antigens are made into homeopathic remedies called allersodes and are given to the patient orally. This has proven very successful in flea allergies. For flea desensitization we use a product called Biting Insect Mix.
Hot spots can occur from a variety of problems and can be treated in several different ways.
I prefer using a homeopathic ointment called Traumeel externally on the spots. Often, when caught early this is enough to dry up the spot. Or this can be used in alternation with colloidal silver. Orally BHI Skin, Inflammation, and Traumeel work well to promote healing and stop the progression of any further outbreaks. These same formulas work well for interdigital cysts too.