"Red Mange"

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The PetStuff Online Newsletter
Volume 1 Issue 6  September 17, 1999


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"Red Mange - Demodectic Mange"

On the Internet Bulletin Boards, I am constantly bombarded by questions relating to "Red Mange" which is properly known as "Demodectic Mange". On doing a little research, I discovered that this is the 6th ranking skin problem in dogs. The condition is caused by a strange little cigar-shaped mite. Fortunately cats are not troubled by demodex mites so "cat people" can relax. People, dogs, swine, sheep, goats, horses, cows and possibly other animals all have individual species that inhabit the normal hair follicles and oil glands in the skin. In other words, you have "critters" camping out in your hair follicles right now as you read this Newsletter.  In normal skin the immune system of the host prevents the mites from reaching large numbers.  They are always being held in check.  In young animals with developing immune systems or in old debilitated animals the situation can get out of control.  The mites are allowed to proliferate and cause the skin disease often referred to as "Red Mange".

"Red Mange" the Disease
When the immune system is compromised for any reason such as when a dog is a juvenile, short haired, malnourished or in poor condition the mites can become numerous in hair follicles.

The "dry form" of the disease (75% of cases) usually occurs in pups 3 to 9 months of age. It starts as scaly, rough areas on the skin with slight hair loss. It centers on the fore quarters with lesions first on the head and neck and then on the forelimbs.  The early lesions resemble a "rug burn" hence the name "red mange".    Occasionally the skin can become hyperpigmented and turn black - "black mange". 

The "pustular form" (10 to 20% of cases) occurs as the condition advances. Opportunistic bacterea such as Staphlococcus or Streptococcus species colonize the affected areas and the condition spreads over large portions of the body. At this stage of the disease, the skin becomes greasy, red, swollen and scabby and has a characteristic "mousy odor". Itchiness from the secondary bacterial infection occurs. The poor dog appears "mangy and ugly. Lymph nodes enlarge due to the systemic spread of the mites and bacteria. From there, the mites and bacteria can enter the blood stream and affect other organs. If allowed to progress, the condition may become fatal due to the overwhelming sepsis.

Diagnosis
Diagnosis is accomplished by deep skin scraping in several affected sites.  The skin is pinched up to squeeze mites out of the hair follicles, mineral oil is then applied and the skin is scraped down until lightly bleeding. The material scraped up is placed on a microscope slide and is examined for the presence of mites.  If large numbers of Demodex mites are present and the dog has the signs listed above a diagnosis is made. If no mites are found and the signs are present then another scraping needs to be done since the mites are often difficult to find if the skin is thickened and severely irritated. Sometimes a skin biopsy must be taken to find the mites.

The life cycle of Demodex Mites
As can be seen in the image below, Demodex mites complete their entire life-cycle in the hair follicles or on the surface of the skin. It is thought that they are transmitted to puppies by direct contact with an infected dam. Eggs are laid >> they hatch to larva >> larva molt to become nymphs >> nymphs molt to become adults.

DemodexLife.JPG (80760 bytes)

How is Demodectic Mange treated?
Treatment is often unrewarding - at best it is only about 70% successful.  This is because if a hereditary condition or other systemic illness continues to depress the immune system the mites can never be erradicated.  Many times, young animals must be treated four to six times until the immune system develops with age. Often, entire litters are infected.  These dams should not be bred as the condition is heritable.

Treatment involves clipping the hair from the affected areas and then shampooing the skin with a good quality degreasing shampoo. The skin is then rinsed with clear water and towel dried.    A dip solution containing amitraz (Tactik or Mitoban®) is then sponged over the entire dog and allowed to air dry. A word of caution: Amitraz can be toxic so protective gloves, eye and face protection should be worn by the person applying the dip.   This process is repeated every two weeks until skin scrapings reveal all dead mites.  This may take from 4 to 8 treatments.  If bacterial infections are present, appropriate antibiotics are also administered. It is very important to not stop treatment too soon. We suggest that the dips be continued on two separate occasions two weeks apart AFTER skin scrapings reveal all dead mites. This ensures a complete kill of all stages of the demodex mite (egg-larva-nymph-adult).

Other treatments include oral Ivomec® which is an injectible cattle wormer.  In mild cases this may be curative in itself or may be included in combination with amitraz dips to improve efficacy.

In dogs unresponsive to amitraz or amitraz/Ivomec® treatments, milbemycin oxime has been used with success. This is an expensive medication but very effective.

Treatment is expensive and frustrating
In my own clinical experience, we have been quite successful in curing our affected patients.  Since amitraz is toxic we do not dispense the product. We do all the dips "in hospital" after retreiving a skin scraping.  All we can do is continue with the scrapings and dips every two weeks until we get scrapings that contain all dead mites. We dip two more times after scrapings are negative.  This can run into quite a bit of expense for owners.   What happens if the condition reoccurs 6 weeks later?  We get screamed at and we go on with the dips until the condition is once again under control. We have seen it reoccur 3 times.  The client hated us!  But...   Today he has his dog and wouldn't give the world for him.  To treat Demodectic mange you have to be prepared to "go for broke" and often times it can take you very close to it.   We hope breeders who produce puppies with this condition take note and stop breeding these animals.  It can be heartbreaking if you discover your new puppy has the "Red Mange".

Can people get Demodectic Mange?
Yes, but not from dogs.    Demodex mites are host specific.

Last Words About Demodectic Mange...
Treat for four weeks AFTER skin scrapings reveal all dead mites. Expect reoccurances. Don't breed dogs that have had Demodectic Mange as puppies - you are passing this trait on to other unsuspecting owners.    The disease usually is curable if you remain patient.

Next Week
September 24th - Sarcoptic Mange - You can get it!
October 1st - Anal Sac Disease & Scooting
October 8th - Buggy Ears - Ear Mites

A Little Humor in Closing

"Rules for Newsletter Editors"

I am so horrible at the mechanics of using the English language, someone felt sorry for me and sent me this article.  I thought it was funny and actually quite helpful.  Thanks Kim...

1. Verbs HAS to agree with their subjects.
2. Prepositions are not words to end sentences with.
3. And don't start a sentence with a conjunction.
4. It is wrong to ever split an infinitive.
5. Avoid cliches like the plague. (They're old hat)
6. Also, always avoid annoying alliteration.
7. Be more or less specific.
8. Parenthetical remarks (however relevant) are (usually) unnecessary.
9. Also too, never, ever use repetitive redundancies.
10. No sentence fragments.
11. Contractions aren't necessary and shouldn't be used.
12. Foreign words and phrases are not apropos.
13. Do not be redundant; do not use more words than necessary; it's
highly superfluous.
14. One should NEVER generalize.
15. Comparisons are as bad as cliches.
16. Don't use no double negatives.
17. Eschew ampersands & abbreviations, etc.
18. One-word sentences? Eliminate.
19. Analogies in writing are like feathers on a snake.
20. The passive voice is to be ignored.
21. Eliminate commas, that are, not necessary. Parenthetical words
however
should be enclosed in commas.
22. Never use a big word when a diminutive one would suffice.
23. Kill all exclamation points!!!
24. Use words correctly, irregardless of how others use them.
25.Understatement is always the absolute best way to put forth earth
shaking
ideas.
26. Use the apostrophe in it's proper place and omit it when its not
needed.
27. Eliminate quotations. As Ralph Waldo Emerson said, "I hate
quotations.Tell me what you know."
28. If you've heard it once, you've heard it a thousand times: Resist
hyperbole; not one writer in a million can use it correctly.
29. Puns are for children, not groan readers.
30. Go around the barn at high noon to avoid colloquialisms.
31. Even IF a mixed metaphor sings, it should be derailed.
32. Who needs rhetorical questions?
33. Exaggeration is a billion times worse than understatement.

Credits
Images used in this publication taken from Hill's Atlas of Clinical Anatomy, Published by Veterinary Medicine Publishing Company, Inc.   A publication donated to veterinarians by the Hill's Pet Food Company to teach clients about their dogs and cats in sickness and in health.   Hill's Pet Food Company produces Hill's Prescription Diets and Science Diet Premium Pet Food.

Have A Nice Week

Later,  Dr Dan