Pups need to be 12 wks or 3 lbs before topical flea prevention can be given. Please make sure its for pups/dogs 0-5 lbs. or under 10 lbs.
Fleas bite and embed themselves so if we see fleas or eggs, we bathe them in dawn dish soap. It kills them without hurting your pup.
Note: astringents such as dawn or whiteners will remove some of the natural oils of your dogs skin. So don't bathe too often and be aware that it can take 5-10 days before the oils replenish. This means if you are going to use a topical flea prevention, wait at least 7 days after their bath to start. The topical preventatives need the oils in the skin in order to work. If you use them too soon after bathing in astringents they will not work. And you will have to wait at least a month before you can reapply a topical preventative.
Fleas bite and lay nests, embedded in your dogs skin. When there is an infestation you may feel something that feels like a scab usually on back of neck. You may see fleas hopping around on their belly's, (that is usually the easiest place to see). You will also see your dog itching. If your going to get a preventative, do not bathe in dawn or anything astringent that will remove the oils from their skin. Go to the vet or any pet supply store to get preventatives. Also get a tapeworm pill . Capstar is great with no side effects to immediate make fleas jump off. I absolutely believe in natural preventatives when possible. However with a flea infestation you don't want to use sprays or flea dips or anything that will burn or hurt your puppy. You want to be as fast as possible to give your puppy or dog relief. Preventatives before flea season is best.
Fleas can cause allergic reaction,s usually dermatitis. It can also cause anemia in a dog, more likely so in a small dog with a prolonged flea infestation. With a puppy, anemia could happen quickly. Fleas (just one ingested flea) can cause tapeworms. Your dog biting will give them tapeworms. If I see a flea, I assume the dog will have tapeworms. If your dog is on worm prevention, your dog is still not protected from a tapeworm. Read more about worms....