Ultimate skin lesions in man and animals similar. Masked by thick
cuticle, pigment, hair, fur, feathers. White, hairless skin. Lesions
and deranged functions: Maculæ, erythema, papules, nodules, blisters,
blebs, pustules, boils, carbuncles, scales, crusts, sitfasts, horny
growths, erosions, abrasions, chaps, fissures, ulcers, excrescences,
cicatrices, neuroses, morbid secretions, changes in glands, hairs, in
derma. Scleroderma. Elephantiasis. Vegetable and animal parasites.
In cutaneous diseases in man and animals the actual lesions are largely
of the same nature, yet in the animal covered with hair, fur or
feathers, and with the cuticle deeply pigmented, the diagnosis of the
different affections becomes much more difficult. On white-skinned
animals and on parts with little or no hair, the identification of the
different forms is usually possible. The following list may serve to
indicate the nature of the different lesions, but these must not be
accepted as indicating distinct diseases, as two or more of these forms
often coexist or succeed each other in the same affection:—
1st. =Maculæ: Spots: Discolorations.= Examples: Black, melanotic spots
in skins of white horses: white spots in dourine, after pustules, etc.:
ecchymosis after contusions, stings, insect bites, etc.: petechial spots
in anthrax, rouget, hog cholera, rinderpest, canine distemper, swine
plague, scurvy, etc.
2d. =Erythema: Rash: Flush.= Congestive redness usually disappearing
under pressure. _Physiological_ in blush or glow of exercise,
_pathological_ from insolation, friction, deranged innervation, etc.
3d. =Papulæ: Papules: Pimples.= Small, red, hard, conical elevations,
not forming blister nor pustule. Due to exudation and the accumulation
of leucocytes at given points, having a local or general cause,
(psoriasis, intertrigo, etc.).
4th. =Tuberculæ: Nodules.= Larger but still circumscribed thickening of
the entire skin from exudation and cell growth, from ½ inch to 2 or more
inches in diameter and sometimes becoming confluent. Examples: Urticaria
(surfeit) in solipeds, and cattle; petechial fever, farcy, etc.
Sometimes chronic.
5th. =Vesiculæ: Blisters.= Rounded or conical elevations the size of a
millet seed to a pea, and having a small liquid exudation under the
cuticle in the centre. In inflammations of the papillary layer, of a
sufficiently acute type the tendency is to the formation of vesicles.
These lesions are, therefore, often present in very different forms of
skin disease from those due to simple thermic irritation, to
constitutional diseases like eczema, or contagious ones like sheep pox.
May merge into pustules or other advanced lesions.
6th. =Phlyctenæ: Bullæ: Blebs.= In these the individual lesion is larger
than in vesicles. They are of any size from a pea upward. The most
striking example is in cantharides, blisters, scalds and burns, but in
other cases it depends on a constitutional condition or a specially
exudative dermatitis.
7th. =Pustulæ: Pustules.= These differ from vesicles in that the central
exudate becomes the seat of suppuration and a limited collection of pus,
at first central, though later involving, it may be the whole area of
the exudate. It is often merely an advanced stage of the papule or
vesicle. We find examples in the different forms of variola, in lesions
caused by tartar emetic or croton oil, and in several forms of
dermatitis. It is essentially microbian.
8th. =Furunculus: Furuncle: Boil.= Inflammatory nodosity of the derma,
resulting in a necrotic central core and suppuration. Is bacteridian and
common on the coronet and lower parts of the limbs in solipeds.
9th. =Carbunculus: Carbuncle.= An inflammatory nodosity or cluster of
nodes of much greater extent, tending to necrotic change and sloughing
over a much more extending area. Microbian.
10th. =Squama: Scales: Dandruff.= Exudation products and cells dessicate
and exfoliate as branlike scales or thicker coherent laminæ. Examples
are found in psoriasis, pityriasis, eczema, variola, rinderpest, etc.
11th. =Crustæ: Crusts: Scabs.= Hard, solidified masses of epidermis,
blood, pus and serous exudate.
12th. =Callositas: Callosity.= Abnormal thickening of the epidermis, as
a physiological protective cell growth. Examples: pads on the knees of
camels, cows and even horses from kneeling on a hard, uneven surface.
13th. =Sitfasts: Necrotic Callosities.= Combination of dried up exudate
of horny consistency, and a thickened, fibroid and partially necrotic
portion of the subjacent derma with little or no disposition to
spontaneous detachment.
14th. =Cornu Cutaneum: Keracele: Horny Growth.= Abnormal horny growth
from keratogenous tissue, or from the derma in its vicinity or at some
other point of the skin.
15th. =Erosions: Abrasions.= Lesions of the cuticle exposing the true
skin, and the result of itching, scratching, friction, biting or other
mechanical or thermic injury.
16th. =Rimæ: Cracks: Chaps.= These are linear breaches often confined to
the epidermis in the bends of joints, under congestion and suppression
of sebaceous secretion, in elephantiasis, dropsy, petechial fever, etc.
Unless they have ulcerated they may heal without cicatrix.
17th. =Crevasses: Fissures.= These are chaps, which extend into the
derma, giving rise to destruction of tissue and leaving a cicatrix on
healing. Examples are found in the hollow of the pastern, behind the
knee (Mallenders), in front of the hock (Sallanders), in the swellings
of petechial fever, malignant catarrh, stocked legs, grease, etc.
18th. =Ulcus: Ulcer.= A sore that extends by the continual molecular
breaking down of the forming granulations and of the adjacent and
subjacent diseased tissue.
19th. =Excrescences: Hyperplasiæ: Phymata: Dermatomata.= These may
include over luxuriant granulations which rise above the level of the
skin and become organized into projecting fibro-cellular, raw or scabby
masses: tumors of all kinds—warty, papillomatous, horny, epidermic,
cancerous, sarcomatous, pigmentary, angeiomatous, tuberculosis, etc.
20th. =Cicatrices: Scars.= These are puckered, raised or sometimes
depressed, lines or areas of condensed connective tissue with a covering
of epidermis, taking the place of the normal dermis and epidermis and
their appendages, which have been destroyed. They result from traumatic,
ulcerous, or atrophic destruction of the skin.
21st. =Neurosis.= These may be exemplified by the intense itching of the
skin without appreciable structural change. So in cutaneous anæsthesia
and hyperæthesia.
22d. =Modified Secretions.= These include absence of
perspiration—anidrosis, excessive perspiration—hyperidrosis,
suppressed sebaceous secretion—asteatosis, excessive sebaceous
secretion—steatorrhea or seborrhea, fœtid sweat—bromidrosis, colored
sweat—chromidrosis, _urinous sweat_—uridrosis.
23d. =Structural alterations in glands and ducts.= Cystic
ducts—hydrocystoma, blocked ducts—acne, inflamed glands—hidrosadenitis.
24th. =Abnormal conditions of the hair.= This embraces baldness,
hypotrichosis, alopecia, excessive growth of hair, hypertrichosis, white
patches, canities, nodular hairs, piedra, brittle hair, fragilitas
crinium, felted hair, plica, trichoma.
25th. =Scleroderma.= Hard, leathery, thickened skin. Examples in old
boars on shoulders, and in other animals.
26th. =Elephantiasis Pachydermia.= Enormous hypertrophy of the skin,
with usually distention of the lymph plexuses and vessels
(lymphangiectasis: see Vol. I).
26th. =Vegetable parasites.= Trichophyton, achorion, microsporon,
actinomyces, etc. (See parasites).
27th. =Animal parasites.= Lice, fleas, diptera, trombidium, Acari,
ixodes, cimex, filaria, coccidia, etc. (See parasites).