I am afraid I am not qualified to be the tie-breaker here. It is so brilliant that you have had your lovely dog from the rescue treated and we are glad to hear no adverse reaction to date. It is going to have to be the vet who administered the immiticide who advises you. Although heartworm preventatives will not kill the adult worms and only the immiticide will do that, you are rightly concerned about any possible re-infection during the period of treatment. Your vet will be able to give you the definitive answer and put your mind at rest.
We would love to hear from you and maybe publish your dog’s story, do let us know how you get on.
All the best
Steroids can be injected or taken orally so that they circulate and influence the entire body—systemic steroids—or they can be used topically. Topical steroids are safer than injected or oral steroids because so little is absorbed that the possibilities of side effects are minimal. Examples of prescription systemic steroids include Prednisone and Methylprednisolone . Examples of prescription topical steroids include eye drops such as Prednisolone Acetate Ophthalmic Suspension (for dogs), hair conditioner (ResiCort®), or Genesis Topical Spray (for dogs).
Cushing syndrome or disease is a condition affecting humans and pets wherein there is an overproduction of steroid hormones. This can either be a result of the pituitary gland doing the increased production or the adrenal gland causing the overstimulation and production of the hormone. In the latter case, often times there is a tumor associated with the condition. In layman's terms, Cushing's is too much cortisol being manufactured in the body. Cortisol affects our ability to respond to stress, helps us fight infections, and keeps blood sugar in check. It does the same in our dogs.