TL;DR: Black crusty bumps on a dog's back are typically caused by skin infections, benign warts, or keratin buildup and are usually not an emergency unless your dog shows signs of illness like lethargy or foul-smelling discharge.
What could be causing the black, crusty bumps on my dog's skin?
- Deep pyoderma, which is a bacterial infection of the skin.
- Follicular casts or sebaceous adenomas, often referred to as "old dog warts."
- Flea dirt mixed with scabs from scratching.
- Hyperkeratosis, a condition where the skin produces excess keratin, resulting in dark, hard protrusions.
Are these black crusty bumps a medical emergency for my dog?
- The urgency level is generally low, as these lesions are rarely life-threatening.
- Monitor your dog closely for signs of a secondary infection.
- Schedule a veterinary appointment within 24 to 48 hours if your dog is lethargic, loses their appetite, or if the bumps ooze foul-smelling discharge.
- If no systemic symptoms are present, a routine check-up is appropriate.
How does taking a photo of the bumps help with my dog's triage?
- High-resolution images allow the veterinary team to examine the distribution and texture of the bumps remotely.
- Photos help professionals differentiate between parasites, fungal infections, and benign growths.
- A visual history allows your vet to track if the bumps are spreading or changing shape prior to your appointment.
Clinical Context (Merck Veterinary Manual)
The presence of crusts on a dog's back, especially when accompanied by follicular papules, pustules, and epidermal collarettes, often indicates a superficial pyoderma. Hyperpigmentation in the same area suggests chronic skin irritation, potentially from pruritus, infection, or inflammation. Generalized lesions including erythema, papules, alopecia, oily seborrhea, edema, hyperpigmentation, and crusts, particularly if aggravated by secondary bacterial infections, can indicate generalized demodicosis. In older dogs, festering toes should be radiographed and biopsied deeply to rule out malignant melanoma.
Chapter: Dermatology
Source: The Merck Veterinary Manual, 11th Edition (Page 981)