Demodectic Mange in Dogs

 Overview:

Mange is a highly contagious skin disease of mammals caused by parasitic mites. There are three types of mites to affect dogs. Demodectic mange, Sarcoptic mange & Cheyletiella mange.  This article looks at demodectic mange.  

Also known as red mange, puppy mange or follicular mange, demodectic mange is caused by the mite demodex canis. Demodex canis lives within the hair follicles & all dogs carry this mite in small numbers, having acquired them from their mother during nursing. Usually they are kept in check & don’t cause any problems,  however, in some dogs the population of mites increases. It is not entirely understood why, but it is believed to be genetic or an immune system disorder.

Demodectic mange occurs in two forms, localised & generalised.

Localised:

• This tends to affect dogs under 12 months of age, where their immune systems aren’t fully developed.

• Thinning hair in small, isolated patches in no more than 4 spots. Typically these occur on the eyes, head, neck & forelimbs.  
• In some cases, the skin becomes red & scaly.
• There may be some itching of the lesions.

Dogs with the localised form display mild symptoms & the condition usually resolves in 6 to 8 weeks.

Generalised:

Generalised demodectic mange may begin as localised & progress to generalised. There are two forms, juvenile onset & adult onset.  Adult onset is commonly associated with an underlying condition which impairs the immune system, cancer is one such disease.

• Widespread patches of bald, red, scaly skin affecting the entire body. As the skin breaks down, sores, crusts & draining tracks are formed.
• Itchiness.
• Enlarged lymph nodes.
• Secondary bacterial infection is common.

Dogs with a history of generalised demodectic mange should not be bred with.

Diagnosis of demodectic mange in dogs:

Your veterinarian will perform a complete physical examination & obtain a medical history from you.

Diagnosis of demodectic mange is made via physical symptoms (ie; lesions) and examination of multiple, deep skin scrapings under a microscope for the presence of large numbers of mites.

Treatment of demodectic mange in dogs:

Treatment of localised demodectic mange is generally not required as 90% of cases will resolve on their own. If treatment is necessary, it will usually be the application of topical medication.

In older dogs, finding & treating the underlying cause is also necessary.

Generalised demodectic mange will require treatment. Which may include;

• Dogs with medium to long coats will need to be clipped prior to treatment to facilitate access to the skin.
• Shampoos are used to flush out the hair follicle, this allows for better penetration of the mite killing medication. This must remain on the dog for 10 minutes before rinsing off. The dog is thoroughly dried afterwards.
• Application of  an insecticidal shampoo  (ie; a shampoo to kill the mites).
• Shampooing will need to be repeated approximately every two weeks.
• Skin scrapes will need to be repeated every two weeks.
• Antibiotics to treat secondary bacterial infections.

Treatment can take many weeks before skin scrapings become negative.

There are some side effects to the insecticides including lethargy, drowsiness, vomiting & diarrhea.

Please note:

The medical articles on this site have not been written by a veterinarian & should not be considered a replacement for a veterinarian visit. The articles are provided for informative purposes only.

Always seek immediate veterinary advice for any problems (health or behavioral) in your pets. 

While great care has been made in the creation of these articles, we cannot guarantee the accuracy or omissions on these pages. If in any doubt whatsoever, seek professional medical advice.