Canine Sarcoptic Mange

Canine sarcoptic mange (canine scabies) is a nonseasonal, intensively itchy dermatitis. It is highly contagious by contact with infected dogs and, rarely, with infested premises. Occasionally, only one dog within a group from the same home will have clinical signs of the disease. Incubation period is up to 30 days after first exposure. Humans exposed to infested dogs are commonly affected. Presented signs are red, itchy papules on arms, neck and beltline which, usually regress in 12 to 14 days. Signs can persist for longer periods of time if numbers of mites are large and the contact with affected animals is prolonged and repeated.

The condition is caused by Sarcoptic scabei or S. canis mites. The mite spends its entire life cycle on the host. The life cycle is completed in 17 to 21 days. Male mites live on the surface of the skin while females burrow into the superficial layers of the epidermis to lay eggs. At room temperature (68 to 77F) all stages can survive off the host for 2 to 6 days. Low temperature and high humidity prolong survival. Mites in the environment can be point sources of infection for other animals.

Diagnosis of Canine Sarcoptic Mange

There is no age, sex or breed predilection. The hallmark of the disease is intense itching. This is one of the most pruritic skin diseases of dogs. Pruritus can always be observed during the examination. Pruritus can be caused by:

Signs of Sarcoptic Mange

Lesions are characteristically present at the edge of the ears, elbows, hocks, chest and abdomen and van become widespread. Not always will all these areas be affected. The primary lesion is the itchy red papule. Later, these become associated with thick yellow-grey, scale/crusts, especially on the ears. Secondary alopecia, thickening and hyperpigmentation of the skin can result. Scratch marks covered with blood and crusts are seen. Redness can become generalized. Inflammation of the lymph nodes is common.

Sarcoptic mange is suspected when

• A very pruritic case does not respond to steroid therapy
• Other dogs and people in the same home with suggestive clinical signs.
• Lesions are seen on ear margins, elbows, hocks, chest and abdomen.
• Affected animals are middle age to old dogs that never had skin problems and, suddenly, developed very pruritic skin condition.

Inflammation of the kidneys may result from secondary streptococcal infection of the lesions.

Treatment of Canine Sarcoptic Mange

Parasiticidal dips are usually prescribed:

• Lime-sulfur 2 to 4% (4-6 oz/gal) is administered every 5 to 7 days for 6 dips. It is the treatment of choice for puppies less than 4 weeks old. puppies need to be air dried after the procedure.
• Organophosphate dips: Paramite or Malathion. Dip every 5 to 7 days for 6 weeks.
• Ivermectin (Ivomec) at 300 mcg/kg per os or subcutaneously at two week intervals for 3 treatments. Most dogs will show significant improvement after 7 to 10 days of treatment. Not recommended to use it in Collies, Shelties, Old English Sheepdogs and Australian Shepherds.

Efficacy and safety of treatment with imidacloprid 10% + moxidectin 2.5% spot-on (Advocate&Reg; Advantage multi&Reg;) were tested in dogs naturally infested with Sarcoptes scabiei or Otodectes cynotis in a field study conducted in France, Germany, Albania and the UK. All Sarcoptes infested dogs were topically treated twice a month. Clinical assessment of skin lesion scores at day 56 showed that with either product >96% of the dogs treated against sarcoptic mange were improved or cured. Only 2 mild, possibly drug-related adverse reactions were observed among all treated animals.

All in-contact dogs and environment must be treated; premises should be treated with flea spray. Discard all bedding. Cats are rarely infested with Sarcoptes scabiei.

References:
1. Scott, Miller, Griffin. Parasitic Skin Diseases. In: Small Animal Dermatology, 5th ed., W.B. Saunders, Philadelphia, PA, 1995
2. Hawkins, J.A., et al.: Sarcoptes scabiei infestation in a cat. J. Am. Vet. Med. Assoc. 3. Efficacy and safety of imidacloprid 10% plus moxidectin 2.5% spot-on in the treatment 'of sarcoptic mange and otoacariosis in dogs: results of a European field studyK. Krieger, 'J. Heine1, P. Dumont, K. Hellmann