Skip to content

How to Know if Your Dog Has Fleas—and What to Do Next

Fleas might be tiny, but they can cause big problems for your dog and your home. Detecting them early can be tricky, especially if you’ve never dealt with them before or are facing the early stages of an infestation. These parasites are skilled at hiding, and often, they’re not noticeable until their population grows significantly. 

In many regions throughout the United States, such as the Northeast, Midwest and Northwest, fleas thrive from late spring to early fall. In warmer climates, like the Southern states, they can be a year-round concern. Regardless, if you’re wondering how to know if your dog has fleas, you’re in the right place—educating yourself is the key to identifying and preventing infestations.

A Background on Fleas: What They Are & Their Risks

Fleas are small, wingless insects that survive by feeding on the blood of mammals and birds. Ctenocephalides felis, also known as the cat flea, is the most common species to affect dogs—despite its name. These pests jump onto your dog’s skin, bite and feed, which can cause irritation, discomfort and potential health risks.

Fleas can be more than just a nuisance, sometimes causing:

  • Skin Infections: Flea bites can trigger allergic reactions, leading to excessive scratching, irritated skin and potential secondary infections.
  • Anemia: In severe infestations, fleas can consume enough blood to cause anemia, especially in puppies, senior dogs or those with other underlying conditions.
  • Disease Transmission: Fleas can carry parasites like tapeworms or spread bacterial infections.

And fleas don’t just stay on your pet. They lay eggs that fall into your carpets, bedding and upholstery—which could turn a simple problem into a full-blown household infestation.

Understanding the Importance of Early Detection

To prevent these health complications and protect your home, researching how to know if your dog has fleas​ is a wise move. By identifying these pests early, you can:

  • Prevent Extensive Infestations: The sooner you spot fleas, the easier it is to stop them from embedding in furniture and laying eggs.
  • Protect Your Dog’s Health: Early treatment reduces the risk of your dog developing more severe symptoms or the other health conditions we discussed.
  • Save Time and Money: Tackling a minor infestation is simpler and less expensive than fighting a widespread one.

Exploring the Common Signs and Symptoms of Fleas in Dogs

Now that you know what fleas are and why early detection matters, it’s time to learn the most common signs and symptoms of fleas in dogs:

  • Excessive Scratching or Biting: If your dog seems unusually itchy or is biting at specific spots, fleas could be the cause.
  • Presence of Flea Dirt: Flea dirt looks like tiny black specks—similar to pepper—that you may spot on your dog’s skin or bedding. If you place some on a damp paper towel, it will turn reddish-brown because it contains digested blood.
  • Red or Irritated Skin: Flea bites cause red, inflamed areas—especially around the middle of your dog’s back to their tail.
  • Visible Fleas: Adult fleas are about 1-3 mm long, reddish-brown and fast-moving. They can be mistaken for other insects, but fleas have flat bodies designed for quick movement through fur. Consider looking up pictures if you think you’ve spotted one.

How to Effectively Check Your Dog for Fleas

Even if you don’t suspect your dog has fleas, regular checks can make a big difference in catching them early. Start by using a flea comb to go through your dog’s fur. Focus on areas where fleas are most likely to be, like the neck, the base of the tail and the belly. As you comb, be sure to check the comb for fleas or flea dirt.

Next, inspect your dog’s bedding—another common place for fleas and their eggs to hide. Look closely at where your dog sleeps to see if you can spot any fleas or flea dirt. It’s also important to check other areas where your dog spends a lot of time, such as carpets, furniture and blankets. Fleas love to hide in these places, so make sure to examine them thoroughly.

Lastly, don’t forget to monitor your other pets. Fleas can easily spread from one animal to another, so it’s a good idea to check cats or other furry family members as well. By keeping a close eye on your whole household, you can catch flea issues before they get out of hand.

How to Treat an Active Flea Infestation

If you discover fleas on your dog, it’s natural to feel overwhelmed and unsure of where to start. The good news is there are several effective steps you can take right away to remediate the situation and protect your pet.

Veterinarian Visit

The first place to start is by contacting your veterinarian. They can evaluate your dog’s specific needs and recommend the best treatment options based on your pet’s health, age and any sensitivities or allergies. In the case of an active infestation, your veterinarian can prescribe fast-acting flea medications. Your veterinarian can also help determine if combining medication with other flea and tick treatment methods may be beneficial for your pet. Mixlab pet pharmacy makes it easy to fill these prescriptions as we carry several leading flea and tick medications that ship with fast and free next-day delivery.

Oral Medications

One popular treatment your veterinarian may suggest is an oral flea medication. These medications not only treat active infections, but they are also effective at preventing them. Many oral treatments also provide protection against other parasites, including ticks. After your dog takes one of these medications, it is absorbed into your dog’s bloodstream. When fleas bite your dog and consume blood, they also ingest the active ingredient in the medication, which leads to their death. The specific mechanism of action varies by medication. 

CAPSTAR®, also known as the compound nitenpyram, is a popular over-the-counter oral medication that doesn’t require a prescription. It works by inhibiting nicotinic acetylcholine receptors in the flea's nervous system, causing paralysis and death. It starts killing adult fleas within 30 minutes of administration. 

Alternatively, highly-trusted prescription options include: 

Topical Solutions

For dogs that might do better with an external treatment, topical solutions are another highly effective choice. These liquid medications are applied directly to your dog’s skin, typically between the shoulder blades, where they spread through the natural oils in the skin and hair follicles. Similar to some oral medications, most topical flea treatments work by disrupting the nervous system of parasites, either through direct contact or ingestion. Many topicals also include insect growth regulators (IGRs), which prevent flea eggs and larvae from maturing into biting adults—breaking the infestation cycle. Some formulas repel ticks and mosquitoes, too.

Frontline Plus® is a well-known, over-the-counter topical treatment. One of its active ingredients, fipronil, disrupts nerve function in adult fleas and ticks to kill them on contact. Its other active ingredient, (S)-methoprene, prevents flea eggs and larvae from developing into adults. K9 Advantix II® is another over-the-counter option that has a similar mechanism of action. Active ingredients imidacloprid and permethrin work together to kill fleas and ticks on contact, while pyriproxyfen acts as an insect growth regulator to prevent infestations from recurring.

Flea Shampoos & Sprays

Aside from prescription treatments, your veterinarian may recommend using over-the-counter flea shampoos or sprays. These products can provide immediate relief by killing adult fleas on contact. While flea shampoos and sprays are usually not enough on their own to eliminate an infestation, they work well when combined with a longer-term preventative plan.

Flea Collars

Flea collars are another over-the-counter option to consider, especially if you’re looking for a budget-friendly solution. These collars release flea-fighting ingredients gradually over several weeks or months, providing continuous protection. While they may not work as quickly as oral or topical medications, they can be a convenient and effective part of your overall flea control plan.

Home Treatments

It’s important to remember that treating your dog is only one part of the equation—you’ll also need to address your home environment to prevent re-infestation. Flea sprays or foggers designed for indoor use can help eliminate fleas hiding in carpets, upholstery, and other fabrics. Regularly vacuuming your home, especially areas where your dog spends time, is essential for removing flea eggs, larvae and adults.

Fabric Washing

Any removable fabrics your dog uses, like bedding, blankets and covers, should be washed in hot water to kill fleas and their eggs. This can break the flea life cycle and reduce the chance of re-infestation.

Outdoor Treatments

If your dog spends time outdoors, treating your yard is another important step in managing fleas. Regular lawn mowing and debris removal eliminate potential flea-hiding spots. Plus, you can use outdoor flea control products specifically designed to reduce fleas in your yard.

Routine Cleaning

Even after treating your pet and your home, ongoing cleaning shouldn’t be overlooked. Flea eggs can hatch weeks after your initial treatment, so maintaining a clean environment is key to preventing a resurgence. Continue vacuuming, washing fabrics and staying consistent with your pet’s flea prevention plan to ensure the infestation doesn’t return.

The Power of Prevention: Avoiding Fleas in the First Place

When it comes to fleas, preventing them is always more effective—and easier—than dealing with an infestation later. Luckily, there are a couple of proactive steps you can take to make your dog’s environment less appealing to fleas and help prevent them from becoming a problem.

Start by staying on top of veterinarian-recommended flea preventatives. The oral and topical medications discussed earlier are often the first line of defense, and consistent use is key. Whether it’s a monthly treatment or a long-term option, keeping your dog on a regular prevention schedule will drastically reduce the chances of fleas finding their way onto your pet. If your veterinarian doesn’t stock flea and tick preventatives, you can rely on Mixlab and our easy refill management process to stay on top of your pet’s medication.

Another important preventive step is to seal any gaps or cracks around your home where fleas might be able to sneak in. Check around windows, doors and baseboards to ensure there are no easy entry points. Additionally, if you’ve recently brought home secondhand items like furniture, clothing or pet supplies, make sure to clean and wash them thoroughly before bringing them inside. 

Wildlife around your home can also bring fleas onto your property. Animals like squirrels, raccoons and rodents are common culprits. To reduce the risk, make sure your trash bins are securely closed and consider using fencing to keep unwanted critters out. With these steps, you’ll be one step ahead in the battle against fleas.

Prevent and Treat Flea Infestations with Mixlab

Now that you know the signs and symptoms of fleas in dogs, you can take action with flea preventatives and treatments. Mixlab offers a range of popular flea and tick medications for dogs of various weights and preferences—including chews, tablets and topicals. Whether you’re dealing with an active infestation or want to stay protected year-round, our solutions are ready to ship with free, next-day delivery. Get proactive, protect your pup and have peace of mind by submitting your prescription now or contacting us.

Read On

Read more