Mange in South African Dogs: Sarcoptic and Demodectic

Two very different diseases

Both are mites, and that is where the similarity ends.

Sarcoptic mange, or scabies, is caused by a burrowing mite that is intensely itchy and highly contagious — to other dogs and to people.

Demodectic mange is caused by a mite that lives normally in the hair follicles of nearly every dog. It only causes disease when the immune system cannot keep it in check, and it is not contagious.

Telling them apart

Sarcoptic: relentless itching, often worse at night, with the dog unable to settle. Crusting on the ear margins, elbows, hocks and belly. Scratching the ear margin often triggers a reflex hind leg scratch.

Demodectic: usually not very itchy unless secondarily infected. Patchy hair loss, often starting around the face, eyes and front legs. Common in puppies, where it is frequently localised and self-resolving.

If people in the house have developed an itchy rash on the forearms or waistline, that points strongly to sarcoptic.

Diagnosis

A skin scraping examined under the microscope. Demodex mites are usually easy to find; sarcoptic mites are notoriously hard to find even when present, so a negative scrape does not rule it out.

Many vets will treat on suspicion where the clinical picture fits. That is reasonable practice, not guesswork.

Treatment

Modern isoxazoline parasite chews, the same class used for ticks and fleas, are highly effective against both types and have largely replaced dips. Expect roughly R200 to R450 a month for a medium dog.

Generalised demodectic mange needs longer treatment and investigation of the underlying cause — it is often a sign of an immune problem, poor nutrition or another disease.

Secondary bacterial infection is common in both and usually needs antibiotics and medicated washing alongside the mite treatment.

The household side

For sarcoptic mange, treat every dog on the property even if only one is itchy. Wash bedding hot and treat the sleeping areas.

People who have picked it up usually clear once the dogs are treated, but see a doctor if the rash persists. Human infestation with the dog mite is self-limiting because the mite cannot complete its life cycle on us.

Street and rescue dogs commonly arrive with sarcoptic mange. Isolate a new arrival from resident dogs until the skin has been checked.