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  Discussion on Thick black scabs with hair loss
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New Member:
Sandydee

Posted on Sunday, Sep 12, 2004 - 2:29 am:

I have a mustang mare that looks to have scars from previous injury on her withers and shoulder. The skin on these areas has gradually over the past year thickened and turned black with hair loss. Biopsy so far has turned up nothing.This thing is sensitive to touch, seems to take on a plastic looking appearance and is hardened on the withers. Any advice is greatly appreciated. I have been using antimicrobial spray that seems to give her some comfort but doesn't get rid of it.
Moderator:
DrO

Posted on Sunday, Sep 12, 2004 - 11:47 am:

I am not sure what to make of this Sandy. This would be the normal appearance of a scar: hairless and black over pigmented skin. Scars once formed cannot be treated away. Sensitivity may be because of the odd feel, the past injury, or just everyone is messing with this area, it may not be a sign of a active disease process. The changes you see may be the treatments you are applying.

Is it uncertain there was an injury to this area? Perhaps a photo would help.
DrO
Member:
Sandydee

Posted on Sunday, Sep 12, 2004 - 2:30 pm:

Thanks for the reply.i am not sure if the scars are from injury..or from this skin condition.I will attach pics and maibe it will help.The first is her withers, second her shoulder

withers
shoulder
Member:
Sandydee

Posted on Monday, Sep 13, 2004 - 11:50 pm:

After looking over other skin issues on this board, I wonder if this may be a form of Linear Keratosis? Any ideas? Thanks
Moderator:
DrO

Posted on Tuesday, Sep 14, 2004 - 8:57 am:

We should be able to rule in or out linear keratosis if you give us a thorough history and the complete biopsy report.
DrO
Member:
Sandydee

Posted on Tuesday, Sep 14, 2004 - 11:50 am:

This mare has been at the ranch for a little more than a year.At first she had what looked like strange scars on her shoulder, and a dry patch on her withers, and a round sunken scar on her rump about 3inches round.The one on her withers has slowly spread wider and gotten thicker and sensitive to touch as well as the shoulder.Use of steroid cream caused it to get very itchy and I noticed some peeling, but not much change.The antimicrobial spray seems to thin the outer edges a bit but the thick area on her withers is still the same.Below is the biopsy for you.Thanks a bunch.Sandy

BIOPSY with microscopic (1 tissue)
Test Value
SOURCE/HISTORY

MULTIFOCAL AREAS/PATCHES OF ALOPECIA, SKIN DARKENING, THICKENING AND
SPREADING. SENSITIVE TO TOUCH. STRANGE WHORL/QUILT PATTERN TO COAT.
DURATION GREATER THAN ONE YEAR.

MICROSCOPIC DESCRIPTION

THE SPECIMEN EXAMINED IS A SECTION OF SKIN IN WHICH THE EPIDERMIS IS
INTACT AND OF NORMAL THICKNESS. THE BASILAR LAYER OF THE EPIDERMIS IS
HEAVILY PIGMENTED. HAIR FOLLICLES ARE ASSOCIATED GLANDS ARE INTACT.
MOST HAIR BULBS IN THE SECTION ARE PROLIFERATIVE, BUT ONE IS
RELATIVELY SMALL AND INACTIVE. HAIR SHAFTS ARE NOT EVIDENT IN SOME
FOLLICULAR SHEATHS. MINIMAL NUMBERS OF LYMPHOCYTES AND OCCASIONAL
MACROPHAGES CONTAINING PIGMENT ARE EVIDENT IN THE LOOSE CONNECTIVE
TISSUE AROUND SMALL BLOOD VESSELS AND ADJACENT TO HAIR FOLLICLES.
BLOOD VESSELS ARE PATENT AND ARE OTHERWISE UNREMARKABLE. ETIOLOGICAL
AGENTS ARE NOT EVIDENT. CONNECTIVE TISSUE IN THE DEEP DERMIS APPEARS
RELATIVELY DENSE AND COLLAGENOUS.

DIAGNOSIS

UNINFLAMED INTACT SKIN WITH SCATTERED EMPTY HAIR FOLLICLES AND
SUSPECTED DEEP DERMAL SCLEROSIS.

COMMENTS

THE CHANGES PRESENT ARE RELATIVELY SUBTLE AND ARE NOT SPECIFIC AS TO
CAUSE. HAIR FOLLICLES ARE INTACT AND MOST BULBS APPEAR PROLIFERATIVE,
BUT THERE APPEARS TO BE LOSS OF HAIR SHAFTS FROM SOME FOLLICLES. SUCH
LOSS IS TYPICALLY TRAUMATIC AND MAY BE RELATED TO PRURITIS. HOWEVER,
THERE IS NO ACTIVE INFLAMMATION PRESENT TO SUGGEST A PRURITIC SKIN
CONDITION. ANY EARLIER PRIMARY INFLAMMATION MAY HAVE SUBSIDED DUE TO
TREATMENT (CORTICOSTEROIDS) OR TO THE PASSAGE OF TIME (IF THIS LESION
IS OF LONG DURATION). ALOPECIA AREATA WOULD BE A CONSIDERATION
ALTHOUGH NO ACTIVE INFLAMMATION IS EVIDENT AROUND HAIR BULBS AT THIS
TIME. SENSITIVITY TO TOUCH IS A FEATURE OF HYPERESTHETIC
LEUKOTRICHIA, BUT THE HAIR IN SUCH LESIONS SHOULD, OF COURSE, BE
WHITE. THERE DOES APPEAR TO BE SOME EXCESSIVE DENSE FIBROUS TISSUE IN
THE DEEPER DERMIS, BUT THIS IS DIFFICULT TO INTERPRET SINCE THE
THICKNESS AND DENSITY OF THE DERMIS VARIES CONSIDERABLY WITH
ANATOMICAL SITE. TRUE DERMAL SCLEROSIS IS OFTEN POST-INFLAMMATORY BUT
MAY ALSO BE IDIOPATHIC. IT IS POSSIBLE THAT MULTIPLE BIOPSIES TAKEN
FROM LESIONS OF DIFFERING DURATIONS MAY BE HELPFUL TO ATTEMPT TO FIND
EARLIER, MORE ACTIVE SPECIFIC CHANGES.

Moderator:
DrO

Posted on Thursday, Sep 16, 2004 - 9:38 am:

Hello Sandy,
I have mulled over your pictures and the histopath description and they don't really match. Your pictures show a thickening with absent hairs, while the description says the sample has mostly normal hair follices and thickness??

Looking at the history and visual appearance, it certainly looks and behaves like LK but the histopath lacks the typical thickening of the epidermis...Perhaps the area examined was early or not typical of the disease process or modified by therapy? There are some things consistant with LK most notably the lack of a identifiable disease. I agree with the assesment that further biopsies may be helpful in the diagnosis but am pretty sure we are looking at a case of LK with the histopath not represenitive of the primary lesions seen in the pictures above.
DrO
Member:
Sandydee

Posted on Thursday, Sep 16, 2004 - 12:05 pm:

Hi DrO, the biopsy was taken off of the very edge of the area.The vet wanted a sample with both the inflamed area and healthy tissue, but it seems it may have been better to get it from the thickest area.I am waiting for a dermatolgy consult to see if I can get anything more definitive.Until then, can you recomend anything I can do to treat this thing?Thanks again for your help.Sandy
Moderator:
DrO

Posted on Thursday, Sep 16, 2004 - 9:29 pm:

Sandy, I am afraid that if it is LK it is not a treatable condition. But neither is it harmful and seems to be self limiting: it does not spread over wide areas of the body. Let's assume we have some other condition. The biopsy does not indicate an infectious agent but the fact that it might be painful (not a characteristic of LK) indicates inflammation from an unknown cause so steroidal cremes seem logical.
DrO
Member:
Sandydee

Posted on Friday, Sep 17, 2004 - 12:10 am:

DrO, thanks so much for the information.I will ask for another biopsy, and see what happens.If it is LK, it's good to know at least that it won't spread...only trouble is that I'm afraid it may be painful for her to be ridden. I certainly dont want riding her to cause her pain.I will keep trying to figure this thing out, and see about a steroidal creme for her.I appreciate your input greatly.Thanks, Sandy
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