Special susceptibility and exposure of posterior pastern region.
Divisions. Causes: local irritants, decomposing manure, chill water,
slush, mud, pools of liquid manure, septic irritation, stones, sand,
lime in mud, salted snow or ice, washing heels, caustic soaps,
stubble, clipped or singed hair, stocking of limbs, lymphangitis,
sprains, arthritis, anæmia, cardiac, urinary or hepatic disease,
parasites, heavy bedding, constitutional predisposition. Symptoms:
redness, heat, tenderness, swollen, erect hairs, lameness, knuckling,
or exudate, crusts, scabs, abrasions, chaps, fissures, ulcers, loss of
pliancy, engorgment of limbs, fœtid secretion. Prognosis according to
cause. Treatment: remove causes, give rest, cleanse limb and stable,
astringent antiseptic lotions, sulphurous acid, carbolic acid,
creolin, lysol, pyoktannin, chrysophanic acid, moderate laxative food,
diuretics, arsenic, bandaging, hand rubbing, exercise.
The affections of the heel or posterior part of the pastern in horses
are largely modified by the anatomical character of the skin in this
region, and the special exposure to inimical agents, so that it is
convenient to consider them under special headings, even though the
eruption may be of the same kind with that seen in other parts. The
dermatitis of this region, which are not primarily contagious may be
conveniently divided into 1st, such as are unattended with free
secretion, and 2d, those that implicate the sebaceous glands and are
marked by an offensive discharge. Cracked heels belong to the former
category.
The _causes_ are extremely varied, consisting in the application of
irritants of many kinds, to the susceptible skin in a system too often
already predisposed to skin disease.
Standing on reeking dungheaps, or on heating manure in filthy stalls
subjects the heels, and especially the hind ones, to ammonia and other
irritating fumes, and when taken out to the cold air, chill water and
mud, the sensitive parts suffer. Again in the farm yard and even in
neglected stalls the hind feet are immersed in pools of liquid manure,
the ferments and toxic matters of which dry on the skin, attack the
surface and determine septic congestions and inflammations. On country
roads where there is no pretense of pavements, or macadam, the mud in
spring and fall is a source of great irritation on certain soils which
contain small flat stones, pebbles or sand, or in which lime or
decomposing manure is a prominent feature. Standing in snow or slush,
especially if chilled by salting, produces partial or complete
congelation with the result of chillblains or even more active and
destructive inflammation or sloughing. The habit of washing the heels
and allowing them to dry spontaneously in the stall is only less
injurious by the chill induced. This is still further aggravated by the
use of caustic soaps on the already tender skin. The lighter breeds of
horses, devoid of long hair on the pasterns, though less subject to the
_greasy_ secretion, are even more exposed to chills and direct injuries,
and suffer readily and often persistently from erythema and cracks. In
many cases trouble comes from the ends of stubble and other vegetables
acting on the skin. A common fault is the close clipping and even
singeing of the hair in the hollow of the heel. The stiff, bristly ends
of the hairs on one fold of the pastern continually prick the skin of
the adjacent fold when the animal is in motion and not only is this
irritating to the healthy skin, but it becomes incomparably more so when
that is congested and tender. Even in summer the deep dust on unpaved
roads, mixing with the normal secretions of the heel, rolls into
semi-solid masses between the folds and proves the more irritating, the
greater the admixture of sand or solid bodies. A common cause is the
stocking of the limbs, with the attendant congestion, distension and
debility of the skin. This may be due in its turn to a great variety of
proximate or remote causes, lymphangitis, sprains, arthritis, osteitis,
anæmia, cardiac, urinary or hepatic disorder, parasitisms, etc., so that
accessory causes must often be widely sought. Even an excess of straw
around the hind limbs will cause stocking in some animals which escape
on bare pavement. Finally we must take into account that constitutional
predisposition in some animals that makes them liable to inveterate skin
diseases under the slightest causes.
_Symptoms._ In the _milder forms_ there may appear a redness, with heat,
tenderness and swelling in the hollow of the pastern, the hairs stand
stiffly erect, and the surface may be perfectly dry. The affected limb
has the pastern more upright than the others and the fetlock starts
slightly forward. In a nervous, sensitive horse the skin is so tender
and rigid, that the animal can hardly be persuaded to use the limb, and
goes dead lame for a considerable distance until it has become more
pliant.
With some aggravation of the condition the skin is felt to be somewhat
rough and uneven by reason of the encrustations of epidermis, dried
secretions and dust over its surface, which may convey to the finger a
slightly oily sensation. In many cases these epidermic and exudation
products form scabby elevations, and a chronic condition of this kind
may persist indefinitely, constituting what is known in America as
_scratches_. This will vary by reason of the detachment of these
concretions with the formation of abrasions and sores of various sizes,
which may heal, or extend by coalescence, chapping, or ulceration.
In other cases, even at an early stage, the formation of chaps or cracks
is a marked feature. At times this may seem to be the result of over
distension in the inflamed superficial layers of the skin which have
lost their natural pliancy and cohesion. They will, sometimes, form
under slight exercise, but not when at rest. They may simply extend
through the epidermis, exposing the papillary layer, or in bad cases one
or more fissures may extend through the integument and expose the
tendons beneath. They may extend forward on the sides of the pastern or
upward over the back of the fetlock and metatarsus.
In all cases, when the local inflammation is acute, some swelling of the
limbs appears, and this keeps pace with the character and extent of the
trouble. With extensive chaps or fissures it becomes extreme, extending
up toward the hocks and attended by great pain and stiffness. The sores
become the seat of active suppuration, with it may be considerable
destruction of tissue. Even in the milder forms there may often be seen
a fœtid muco-purulent secretion in the depth of the folds of the
pastern, and in the worst cases this extends to the whole surface after
the manner of _grease_.
_Prognosis._ The milder uncomplicated cases recover readily and
perfectly under rest and judicious treatment; the more advanced cases
are liable to leave swelled legs with susceptibility to a relapse, and
in cases associated with a constitutional diathesis or chronic internal
disease, recovery may become problematical and uncertain.
_Treatment._ In all cases the cause must be done away with, whether
filthy stalls, reeking dunghills, septic pools, work in irritating road
mud, or melting snow, washing the heels with caustic soaps, drying them
in cold draughts, pricking with stubble or clipped hairs, and all the
causes of stocking of the limbs. If heels are washed, use pure tepid
water, and, if necessary, the best Castile soap, and rub them dry at
once. If this cannot be done bandage them rather than leave them in a
cold draught.
Give rest in a clean stall and thoroughly clean the affected heel, then
wrap in a bandage wet with an acetate of lead or sulphate of zinc lotion
(1 ∶ 50), or apply benzoated oxide of zinc, or cream of glycerine and
salicylic acid.
When chaps have formed they will often promptly heal under standard
solution of sulphurous acid 1, glycerine 1, and water 1. This is applied
on soft cotton and covered by a rubber bandage to confine the acid. The
sulphurous acid solution should be recently prepared, since it will
prove injurious if it has oxidized into sulphuric acid. To one or other
of these preparations the addition of a little carbolic acid, creolin,
pyoktannin, or lysol will often prove useful. When the cracks have
healed, zinc ointment, chrysarobin ointment, chrysophanic acid 1,
vaseline 15, or other soothing and antiseptic agent may be employed till
all inflammation has subsided, and the animal must not be returned to
work until the skin has been restored to its former healthy and elastic
condition.
It may be desirable to greatly restrict the grain during treatment and
even to giving cooling laxatives or diuretics. With a constitutional
diathesis arsenic or other alterative may be tried, and any internal
disease must be attended to. For stocking, use careful bandaging,
hand-rubbing and exercise.
With the formation of the deeper fissures the same antiseptic agents may
be employed, or salol, iodoform, glutol, aristol, or some tincture of
iodine, or iodide of starch may be used. A weak solution of copper
sulphate has often an excellent effect. The measures advised below for
_grease_ will usually apply in this condition.
SEBORRHŒA OF THE DIGITAL REGION: DIGITAL IMPETIGO, GREASE: STREPTOCOCCIC
DERMATITIS IN HORSES.
A sequel of erythema or cracked heels. Causes: constitutional
predisposition in lymphatic draught horses, rare in ass and mule,
anatomical conditions, wet damp regions, digestive disorder,
overfeeding and lack of exercise, diseases of liver or kidney, change
to stable life, cold water, slush, mud, salted snow, steaming manure,
urine in mares, infection, streptococcus pyogenes. Symptoms: swelling,
heat, and tenderness of pastern hollow, itching, hairs erect, unctuous
exudate, vesicles, excoriations, discharge opaque, grayish, sticky,
fœtid, chaps, knuckling, resting on toe, kicking: in severe cases
discharge purulent, more opaque, sloughs, excessive granulations,
“grapes,” extensions forward, upward, downward, canker, quittor, sand
crack, etc. Lesions: first, congestion of derma, hair follicles full,
hairs loose, connective tissue infiltrated, or thickened, ligaments:
and bones involved, grapes in superposed clusters pediculated.
Diagnosis: from horsepox. Treatment: remove causes, secure
cleanliness, laxative, diuretics, moderate grain ration, or tonic
regimen; locally, soothing antiphlogistic, antiseptic treatment, lead,
zinc, phenol, creolin, lysol; when advanced, antiseptic dusting
powders, calomel, salicylic acid, iodine, zinc oxide, salol, or
solutions, zinc chloride, tar. Value of changes. For “grapes” actual
cautery, excision, ligature.
This may develop as an advanced condition of the erythema or cracked
heels already described. Yet it is so distinctive in its habit of
profuse secretion, the eruption of vesicles or pustules and the
abundant, fœtid sebaceous discharge that it deserves a special
consideration.
_Causes._ Something depends on constitutional predisposition. This is
preëminently a disease of the heavy, lymphatic, draught horse, being
rare in racers and trotters, with fine sinewy limbs, no long hair on the
fetlock, delicate skins, and less abundant sebaceous glands. It is
almost, though not quite, unknown in the spare limbs of ass and mule,
and though claimed by Reynal as attacking cattle its occurrence is
equally rare in them. Much of this may be attributed to conformation.
The limb of the draught horse is so much thicker and coarser, with a
great excess of connective tissue and lymph plexus which become readily
gorged in idleness, inducing stocking, congestion and debility of the
whole limb. This same condition operates as a powerful predisposition to
lymphangitis. Again the great length and profusion of the long hairs,
entails the necessary compliment of an excessive development of the
sebaceous glands which become over-stimulated by congestion, and afford
a much more open and favorable infection atrium for the pus microbes.
These structural conditions are much more marked in the draught horses
of wet regions as in Ireland, the western counties of Great Britain,
Belgium, Holland, and the Atlantic provinces of France, and in these the
affection is remarkably prevalent. In our Eastern States and on the
Plains, where the progeny of imported draught horses lose their digital
hair, the malady is comparatively rare. A similar immunity has long been
noticed in the horses of Spain and Africa. Disturbances of the digestion
in heavily fed horses, subjected to transient confinement in the stall,
and diseases of the liver and kidneys, must be recognized as further
predisposing causes. The age of five and six when many horses change
hands, and are subjected to extreme changes of stabling, feed and work,
has furnished the greatest number of cases.
External causes we find in all those conditions already enumerated which
favor chapped heels. Wet, mud, gritty masses, irritant fumes of manure,
cold, heat, filth are potent factors. In connection with these are the
pus and septic microbes that are always present in stables, farm yards,
manure, street dust, etc. No one of these can be adduced as the constant
and exclusive cause, and it is inevitable that a complex infection
should be present, yet the propagation and persistence of the disease
may often be connected with the streptococcus pyogenes.
As emphasizing the importance of such external irritants and infections,
it should be noted that the disease bears an appreciable relation to the
filth and wet of the stable and farm yard, and to the absence of
cleanliness in dealing with the feet, and that the extension of good
pavement and protection from road mud have invariably lessened its
prevalence. The irritant action of the urine renders mares more
susceptible in the hind limbs than horses.
_Symptoms._ The disease may appear as a swelling, heat and tenderness of
the hollow back of the pastern, involving the fetlock and lower part of
the metatarsus or metacarpus, and this may last for one or two weeks,
the engorgement lessening or disappearing during exercise and
reappearing when at rest in the stall. The local tenderness is great as
manifested by the prompt and excessive lifting of the leg when the heel
is touched, as well as by the lameness when first moved, which subsides
with further exercise. Itching may be shown by kicking the floor, or by
a disposition to rub the pastern. The hairs of the affected part are
rigidly erect, and a slightly moist, soapy sensation is felt on the
skin. Close examination may detect the presence of small vesicles with
as yet limpid contents, but the greater part of the liquid product is
traceable to the openings of the hairs and gland ducts. This is followed
by small excoriations taking the place of the ruptured vesicles, and the
discharge becomes more profuse, opaque, white or grayish white, sticky,
and fœtid. It covers the entire affected surface, mats together the hair
in tufts and forms a thicker grayish border. The hairs are loosened in
their follicles and easily pulled out. The erosions become complicated
by chaps, and the swelling increases around the pastern and above the
fetlock. When at rest in the stall the foot may be rested on the toe
only, or held suspended and occasionally kicked backward as if to
dislodge the cause of irritation, yet if moved the patient may gradually
get over the greater part of the lameness, and the swelling partially
subside.
In severe, protracted cases the discharge becomes essentially purulent,
but often with a darker, greenish, reddish or blackish tinge, and
portions of the skin may slough, leaving deep intractable sores. Still
more commonly the raw surfaces become the seat of hypertrophied
granulations, which grow out to form raw, red fungous like, pediculated
neoplasms familiarly known as _grapes_. Between these the spaces are
filled with tufts of hairs and the condensed discharges, in process of
active septic change, and giving off a most repulsive odor. Like the
preceding eruption these _grapes_ may extend around the front and sides
of the pastern, and upward beyond the fetlock, but especially behind.
This advanced condition shows no tendency to spontaneous recovery and
the connective tissue and lymphatic plexus becoming involved, the leg
often swells to enormous dimensions, from six to twelve inches in
diameter at the fetlock. It may last indefinitely until the patient is
worn out, or it may extend to other organs by contiguity or embolism.
Canker of the frog and sole, fistula (quittor), sand crack and seedy toe
may be named as complications, also septicæmia or pyæmia with abscesses
in the lungs, liver, brain or bowels.
_Lesions._ In the first stage there is mainly the congestion of the skin
extending into the large and numerous hair follicles of the pastern. If
pressed, a transparent serum bedews the surface, and if sectioned the
follicles around the hair bulb are seen to be distended by a similar
product. The hairs are easily pulled out. The subcutaneous connective
tissue is filled with a yellowish serosity and at intervals may be seen
a red point of vascular stagnation or blocking. Later these products are
more abundant and those on the now swollen and excoriated surface are
distinctly fœtid. The infiltrated lymph plexuses in the connective
tissue are more distended, their walls thickened and consolidated, and
the rigid skin is thus firmly bound to the structures beneath. A careful
examination shows the presence of subepidermic vesicles of various
sizes. The congestion may extend deep enough to involve the periosteum
of the digital bones and the ligaments of the joints. The _grapes_ are
each attached by a pedicle from which branch out cauliflower-like, fine
papillary processes, that aggregate into a solid cluster. They are very
vascular and grow out cluster above cluster until they reach large
dimensions.
_Diagnosis from Horse Pox._ Since the days of Jenner the claim has been
constantly made that _grease_ and _horse pox_ were one and the same.
Horse pox is however to be distinguished by its transient course, its
inoculability, its incubation of three days, its abundant exudate
concreting on the hairs of the pastern as a yellow mass suggestive of
crystalline structure, by the red pit in the skin in which this mass is
imbedded, by the spontaneous recovery in about 15 days, and by the
immunity on a subsequent inoculation. It is communicable to cattle and
to man, producing the characteristic large umbilicated vesicle and scab.
_Treatment._ The first consideration is to remove the causes of local
irritation and infection, give a clean sweet stall, with dry floor, and
allow no contact with putrid liquids, mud, cold water, melting snow or
other irritant. If exercise is needful to obviate _stocking_ of the legs
give it on dry clean ground.
If inflammation runs high with fever and costiveness a laxative will be
valuable and it may be well to follow this in some cases with cooling
diuretics. When the animal has been on a heavy grain ration this should
be largely cut down in keeping with enforced idleness, or restricted
work. If on the other hand condition is low, and the discharge profuse a
more generous ration may be desirable.
Local treatment is essentially soothing and antiphlogistic, and in view
of the infection should be antiseptic. _White lotion_ (acetate of lead
and sulphate of zinc of each ½ oz., water 1 quart) has been long used
with fair success, for although lead sulphate is thrown down, it is in
part freed again through contact with the exudate. It will be materially
improved by the addition of 1 dr. carbolic acid, creolin, lysol or
chloro-naphtholeum or by some other antiseptic. Lead acetate alone with
an antiseptic is an excellent substitute. In mild cases the surface may
be wet with the lotion several times a day: while in severe ones the
lotion may be applied on a bandage kept constantly wet. When secretion
is well established it may be better to use dry applications, as
calomel; salicyclic acid 10 parts, with iodine 10 parts; calomel and
lamp black; carbolated oxide of zinc or burned alum, salol, etc. After
washing and drying the skin, dust this freely even into the deepest
wrinkles and cover with cotton and bandage. Dress twice daily. For very
fœtid cases, Robertson recommends zinc chloride 1 oz. in 1 qt. water
with the addition of glycerine and phenol, and again a saturated
solution of copper sulphate with carbolized glycerine. For profuse
secretion after the subsidence of active inflammation Renal highly
recommends wood tar with 5 to 10 drops of sulphuric acid to the ounce.
Under these circumstances a powder of gloss starch 5 ozs. with iodine ½
oz. may be employed twice daily. Or again, 1 oz. each of carbolic acid,
tincture of iodine and glycerine may be employed. When one agent seems
to be losing effect, it is well to change for another and never to
neglect the regular dressing, until full recovery has been secured.
In case of _grapes_ the actual cautery is the most efficient measure.
Heat a blacksmith’s fire shovel to a bright red and use this to cut
through the pedicles, a cool shovel being kept constantly beneath it and
in contact with the pedicles, so as to protect the adjacent skin from
injury by the radiated heat. The lower shovel must be dipped in cold
water at very frequent intervals to cool it and prevent cauterization of
the skin between the pedicles. This not only removes the diseased and
infected masses, but leaves the stumps of the pedicles aseptic. Another
method is to cut off the “grapes” and staunch the blood with the actual
cautery at a dull red heat. Still another is to tie the pedicle of each
excrescence separately so as to cut off circulation and secure
sloughing. This is, however, a long, tiresome process, and entails
prolonged contact with much infecting dead tissue. After either method
the parts must be dressed with antiseptics, and dealt with generally
like cases in which the excrescences had not formed.