Ringworm on Dogs: Visual Identification and Management

Ringworm Appearance on Dogs

Ringworm in dogs frequently manifests as circular areas of hair loss, though its presentation can vary significantly. It's crucial to understand that despite its name, ringworm is not caused by a worm; it is a fungal infection.

Key Characteristics of Canine Ringworm

Ringworm, medically termed dermatophytosis, is a fungal infection, not a parasitic worm. This common misconception stems from the circular appearance of the lesions (Source 3, 4). This fungal infection is highly contagious, capable of spreading from dog to dog, and even to humans (Source 1, 3). Ringworm can develop on any part of a dog's body (Source 2).

Visual Characteristics of Ringworm Lesions

Circular Bald Patches

One of the most recognizable signs of ringworm in dogs is the presence of circular or irregularly shaped patches where hair has fallen out (Source 2, 5). These patches can vary in size.

Reddened Skin

The skin within and surrounding these bald patches often appears red or inflamed (Source 2). This redness is a common inflammatory response to the fungal infection.

Scaly or Crusted Skin

Affected areas may exhibit dandruff-like scales, scabs, or crusts (Source 2, 5). This flakiness is due to the fungus affecting the outer layer of the skin.

Darkened Skin

In some instances, the skin within the ringworm lesion can become darker than the surrounding healthy skin (Source 2). This hyperpigmentation can be a chronic change.

Brittle Hair

Hair within or at the edges of the lesions may appear dry, brittle, or break off easily (Source 2, 5). This occurs because the fungus attacks the hair follicles.

Raised Edges

While more commonly observed in humans, some dogs may develop lesions with slightly raised, red borders (Source 2, 3). This classic "ring" shape gives ringworm its name.

Pimples or Bumps

Occasionally, small bumps or pustules may appear within the affected areas. These can indicate a secondary bacterial infection or a more intense inflammatory response.

Itchiness

Dogs with ringworm often experience itchiness, leading them to scratch, lick, or chew at the affected areas (Source 5). This can further irritate the skin and spread the infection.