REMEDY FOR "SCRATCHES"
by Heather Smith Thomas
http://www.anvilmag.com/farrier/101f5.htm in the Jan­u­ary 2001 Issue of Anvil Mag­a­zine
Note: Images with cap­tions are included at the end of this article.

*Pub­lished

‘Scratches’ is a term that refers to a skin prob­lem on the lower legs of horses, caused by a fun­gus (and some­times com­pli­cated by bac­te­ria). The affected area...

becomes crusted, scabby and thick­ened, cre­at­ing bumps and some­times open sores. In severe cases the affected skin may ooze or the whole lower leg may swell, and the horse may become lame. This skin con­di­tion gen­er­ally affects unpig­mented skin (the areas of white leg mark­ings) more read­ily than dark skin, since the unpig­mented skin is not as tough-and more apt to chaff and scrape, open­ing the way for infection.

Scratches is a der­mati­tis, or inflam­ma­tion of the skin, and the most com­mon cause seems to be the fun­gus Sporotrichum schenki. Some horses seem to be more sus­cep­ti­ble than oth­ers, just as some seem more vul­ner­a­ble to other fun­gal infec­tions such as ring­worm and girth itch. The fun­gus lives in organic mat­ter and enters through breaks in the skin when the horse walks through con­t­a­m­i­nated pas­tures or muddy, swampy areas.

The der­mati­tis that results is basi­cally an inflam­ma­tion of the deeper lay­ers of the skin, some­times involv­ing the blood and lymph ves­sels. The most com­mon site of inflam­ma­tion is the pastern and fet­lock area, often in the heel and back of the pastern where the foot bends. The involved skin becomes warmer, red­dish and thick­ened. Then the skin sur­face becomes scabby and cracked, and if the con­di­tion is not treated it usu­ally becomes badly cracked and ooz­ing and spreads to include larger areas. Infec­tion may also spread to the inner tis­sues and is some­times com­pli­cated by bac­te­r­ial infec­tion as well. The thick­ened skin may come off, leav­ing bare spots cov­ered with rough skin, or raw areas.

Tra­di­tional treat­ments for scratches were astrin­gents like meth­yl­ene blue, iodine mixed with glyc­er­ine, or oint­ments made with zinc oxide, nitro­fu­ra­zone and steroids. But a bet­ter treat­ment, rec­om­mended by sev­eral vet­eri­nar­i­ans, is a mix of nitro­fu­ra­zone, DMSO and thi­aben­da­zole (a cat­tle wormer that is also a good fungicide).

Thi­aben­da­zole cat­tle wormer paste is hard to find any­more, how­ever (no longer being sold by most vet­eri­nar­i­ans or mail order live­stock sup­plies because newer drugs have become more pop­u­lar), so the horse­men can sub­sti­tute any of the other ben­z­im­i­da­zole dewormer drugs, found in horse paste worm­ers. Some of these are fen­ben­da­zole (mar­keted as Safe-Guard or Panacur), cam­ben­da­zole, oxy­ben­da­zole (mar­keted as Anthel­cide EQ), oxfen­di­zole (trade name Ben­zelmin) and mebendazole.

The area on the horse’s leg to be treated should first be scrubbed thor­oughly to remove all dirt, then the mix­ture can be applied to the affected part of the leg. The mix should be one part nitro­fu­ra­zone oint­ment (an antibi­otic salve), one part dewormer paste con­tain­ing thi­aben­da­zole or any of the other benizmi­da­zoles, and one part DMSO. These ingre­di­ents can be obtained from a veterinarian.

The DMSO (dimethyl sul­fox­ide) helps reduce swelling and inflam­ma­tion, and also helps the fungi­cide (the wormer paste’s active ingre­di­ent) pen­e­trate the area deeply and thor­oughly, tak­ing the med­ica­tion into the under­ly­ing tis­sues. The nitro­fu­ra­zone com­bats any bac­te­r­ial infec­tion that may accom­pany the con­di­tion, and it helps buffer the DMSO so it won’t burn or irri­tate the tis­sues. The wormer paste kills the fungus.

The dewormer is the safest type of fungi­cide to use in con­junc­tion with DMSO, accord­ing to our vet­eri­nar­ian, since it is an oral med­ica­tion, safe to use inter­nally in the body. Harsh or poi­so­nous fungi­cides like iodine should never be used with DMSO because the DMSO car­ries the med­ica­tion into the body and could cause seri­ous problems.

The affected area should be well cleaned before apply­ing the med­ica­tion, so no dirt or out­side con­t­a­m­i­nants are car­ried into the deeper tis­sues by the DMSO. Warm water is usu­ally ade­quate for wash­ing the leg, and a handy way to apply it is with a well-rinsed dish­wash­ing deter­gent squeeze bot­tle, using your fin­gers to remove any dirt that is cling­ing to the leg from the oint­ment applied at the last doc­tor­ing session.

After the area is washed with warm water and is very clean, it should be dried it with a towel. The skin should not be wet when the mix­ture is applied. A mix can be made that will be enough for sev­eral doc­tor­ings, or it can be mixed up fresh each time-just the amount needed for one appli­ca­tion. It can be eas­ily stirred up with a fin­ger, in a small wide-mouth jar. If a per­son doesn’t want skin con­tact with the DMSO, rub­ber gloves can be used to mix it and to apply it to the leg.

Mixed with nitro­fu­ra­zone oint­ment, the DMSO doesn’t burn or irri­tate the skin or raw tis­sues like it can when used by itself, but a per­son may still ‘taste’ it if your skin comes into con­tact with it. If using bare fin­gers to mix or apply the med­ica­tion, hands should be washed imme­di­ately afterward.

If applied daily, this mix­ture usu­ally clears up scratches faster than tra­di­tional treat­ments. Ban­dag­ing, even in severe cases, is unnec­es­sary, and can actu­ally be detri­men­tal to fast heal­ing. The mois­ture should not be held in.

With this treat­ment a bad case of scratches can be cleared up even if the horse must be rid­den and con­tin­ues to get the area wet and dirty when trav­el­ing through mud or on a dusty trail. The leg should be washed and med­icated each day after the ride. For a really resis­tant case that has bac­te­r­ial com­pli­ca­tions, you can also give the horse oral sulfa tablets to help com­bat the bac­te­r­ial infec­tion, and dex­am­etha­sone to aid in reduc­ing the swelling and inflam­ma­tion, accord­ing to our veterinarian.

The best pre­ven­tion for scratches is to keep white-legged horses out of muddy pas­tures. The fun­gus, once intro­duced into a pas­ture, remains there indef­i­nitely, and horses are apt to pick it up when there are cracks or breaks in the skin. Pink skin chaps, cracks or nicks more eas­ily than tougher, darker skin; that’s why the prob­lem is most com­mon in horses with white leg mark­ings. If a horse must walk through mud or water often, the skin may tend to chap or crack more read­ily, and the fun­gus may be picked up from the mud. Scratches can also be a prob­lem in win­ter pas­tures, and even dry sum­mer pas­tures if the fun­gus exists in the dust and dirt and is intro­duced through breaks in the skin. But if caught early, a few treat­ments will clear scratches right up. A more seri­ous, neglected case will take a bit longer.