A cuddle session with your dog can be comforting and relaxing for both of you. However, feeling scabby bumps on a dog while petting him can tip you off to a host of issues that make him itchy, uncomfortable, and at risk for infection. A skin allergy related to something in the environment, their food, or an allergy to fleas is the most common reason for skin bumps that are crusty on dogs.
Watch out for allergies
Other allergies besides flea saliva can cause crusty bumps on a dog. Just about anything in your dog's environment is a potential source, especially for breeds particularly prone to allergies. For example, a hike where your dog sniffed through some weeds or plants could cause a breakout. If you've changed your laundry detergent, your pet could break out from contact with her bedding, or even be allergic to her pet shampoo.
Food allergies also make your dog itch, most often scratching their ears or gnawing on their feet. Allergies that cause your dog to scratch can lead the way to yeast, bacterial, or fungal infections according to the American Kennel Club (AKC), causing those crusty bumps on your dog.
Allergies can progress beyond scabby bumps on your dog. Watch out for hives or facial swelling around the lips, which can be an early sign of anaphylactic reaction. Severe allergic reactions can be fatal, so call your emergency vet immediately if these symptoms appear.
Check for parasites
If your pet encountered fleas, mites, or other parasitic pests, there might be more than one raised scab on your dog. Some dogs suffer allergic reactions to the saliva of fleas — a condition known as flea contact dermatitis — leaving parts of their body covered in itchy red, crusty bumps, says the AKC. Look for tiny black spots on your dog's skin, known as flea dirt, that could indicate a flea infestation. The base of the tail, underarms, and other places on your dog's body that are warm and moist might harbor fleas.
Mites are another common pest causing scabby bumps on a dog. Known as sarcoptic mange explains Dog Health Guide, the scabies mites can pass from dog to dog or from a wild animal to your dog. The intense itching caused by the parasites leads to scratching that results in hair loss, scabs, and sometimes infection. A lime-sulfur dip coupled with a spot-on anti-parasitic such as Revolution or Frontline can rid your pet of the pests. However, beware of using products containing Ivermectin cautions the Merck Veterinary Manual.
Check for fungal infections
Crusty bumps on a dog could also be a sign of a fungal infection. Dogs most often contract fungal infections from spores in the soil, according to Dog Health Guide. But they can also pick them up from other animals and sometimes even from humans.
- Blastomycosis produces round sores that ooze and crust over. The fungal infection invades the entire body, causing fatigue, weakness, loss of appetite, and sometimes blindness.
- Ringworm isn't a worm at all, but the round, scabby sore on a dog's skin looks as though there's one just beneath the surface. You could catch this from your dog, so watch for telltale signs on your skin should your dog get this fungal infection.
- Yeast infections of the skin often look greasy and produce smelly, scaly skin. When your dog scratches, he can cause little sores that crust over.
- Histoplasmosis most often causes lumps on your dog's neck and systemic maladies such as diarrhea and weight loss. However, there could also be crusty bumps on your dog.
Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.