The parasites are of two kinds, animal and vegetable.
The principal animal parasites are the Acarus scabiei, or itch mite; the Pediculus, or louse; the Cimex lectularius, or bedbug; the Pulex irritans, or flea; and the Pulex penetrans, or chigoe.
The bite of the Cimex lectularius causes a hyperaemic papule with a small red spot in the centre. That of the flea produces a little circular erythematous spot, which exhibits a dark speck in the centre, that marks the wound made by the insect. The chigoe attacks the feet and hands, entering the skin beneath the nails or betwixt the toes, or upon some portion of the extremities, either by a channel made for itself, or by the ducts of the skin; its tracks can sometimes be traced as an elongated brown spot.
The application of a lotion of glycerine and water, of each 3jj, and tincture of calendula 3j will be found very useful in allaying the irritation in the case of the first two. The treatment of chigoe disease consists in dilating the original channel of entrance, and carefully removing the chigoe bodily; after which apply an ointment composed of lard and salt.
Certain caterpillars, if they get upon the skin, may excite urticaria also.
Children of lymphatic temperament who are not kept clean, are poorly nourished, or insufficiently clothed, and live in rooms badly ventilated, are particularly liable to vegetable parasitic diseases; and unless measures are adopted to remove the exciting causes and predisposing conditions treatment is unsatisfactory and relapses are frequent. The patients should be isolated whenever practicable.
The varieties are: Tinea favosa, or favus; tinea tonsurans; tinea circinata; tinea versicolor; and onychia parasitica.
Phthiriasis.
Phthiriasis is the name applied to the affections produced by the invasion of the there well known varieties of pediculus- namely, the head-louse, body-louse, and pubic or crab louse.
The nature and appearance of these insects are so well known that we need not describe them. The first of these infest the scalp; the second confines itself to the non-hairy portions of the surface; and the third prefer the pubic region, but may be met with wherever the hairs are short, but avoiding the scalp.
Phthiriasis Capitis.
This affection occurs most frequently in children, more rarely in women, and almost never in men. The insect (bediculus capitis) finds its most congenial abiding-place in the hair of children, where it lays its eggs, and attaches them by a kind of cement to the shafts of the hair. The eggs take but a few days to hatch, and in a short time the parts may become pretty thickly settled. Then derive their nourishment from the skin, and by their presence produce considerable itching and lead to a corresponding amount of scratching. In children predisposed to eczema they not infrequently lead to the development of this affection.
The diagnosis is, of course, readily made, as inspection of the scalp will quickly reveal the presence of the insects and their ova, if at all abundant. In doubtful cases the fine-tooth comb will soon settle the question.
The treatment, of course, involves the removal of the insects and their ova, usually called “nits.” In children, clipping the hair as close as possible, or perhaps shaving it, is, of course, the quickest way of relieving the patient of these pests. When this is not practicable, the scalp should be thoroughly washed with tincture of staphisagria, or with ordinary kerosene oil. A few applications will kill the living insects, but do not appear to destroy the vitality of the ova. These should be removed as far as possible with the fine-tooth comb. Many., however, will still remain, and the best way to get rid of them will be to go over the scalp carefully and clip the shafts of all the hairs to which they are attached. The head should be washed for a week or ten days, for fear some of the eggs may have escaped detection. It is almost needless to say that soap and water, freely used, are essential adjuvants to the means just mentioned.
The following is a very excellent application: Rx. Ol. Staphisagriae, z3j.
Ol. Limonis, dr.j.
Ol. Amygdalae, z3iv.
M. Sig.: Apply to the affected parts daily.
Phthiriasis Corporis.
This affection is very rarely met with in young persons, and is found most frequently in middle and advanced life, and especially in the feeble and ill-fed, and among the frequenters of prisons and cheap lodgings. Though sometimes met with in women, nine-tenths of the cases are among men.
The pediculus corporis does not lodge upon the body, but infests and breeds among the folds of the under-garments, from which hiding places it sallies forth to seek its nourishment from the skin. This it pierces with the sucker, and continues to feed until gorged with blood. These insects excite at times a lively, and most annoying itching, and lead to vigorous scratching. In cases that have lasted for any length of time, the skin gradually darkens, even to the color of a mulatto.
Diagnosis.-After a little experience a case of phthiriasis will, in most cases, be recognized at a glance, and should always be proved by a careful search for the insects. Strip the patient, if possible, and then examine not his skin, but his shirt, and, as a rule, you will find the pediculi, of present, without difficulty.
Treatment.-Soap, water, and clean clothes are all that are necessary. The old clothes should be destroyed, or thoroughly disinfected by boiling or baking.
Phthiriasis Pubis.
The pediculus pubis affects a preference for the pubic region of both sexes, but is not confined to this locality; but in women may also be met with in the axillary region and in the eyebrows, and in men among the chest hairs and in the beard and whiskers. It rarely gives rise to as much irritation as the other varieties of pediculus, and its presence is often discovered accidentally. The insect attaches its eggs to the hairs like the pediculus capitis, and adheres to them itself or to the skin in the most tenacious manner by the aid of its crab-like claws.
The diagnosis is to be made by the discovery of the insect, but, having been found in its favorite seat, thorough examination of all other parts of the body liable to be infested should not be omitted.
The treatment of this affection involves the employment of some anti-parasitic application, and the one most in vogue is the common “blue ointment.” When, however, the patient will consent to it, shaving of the affected parts is to be preferred. The affection is most frequently contracted during sexual intercourse, but may be derived from wearing infected clothing, or sleeping in an infected bed The patient’s under-clothes and bed-clothes should be boiled or baked, in order to destroy the insects;and their eggs.
Psorospermosis
Psorospermosis may be defined as a condition of the skin of varied lesion, but characterized by the presence of “psorosperms.” The psorosperm is a living animal parasite, which infests the human skin as well as the bodies of some of the lower animals, and consists of a roundish or oval cell, containing one or more nuclei; the nucleus occupying but a small portion of the cell, the plasmic portion of which is extremely transparent and structureless.
Much doubt exists among dermatologists as to the nature of this affection; and but little is known positively concerning it.
Scabies.
Scabies is a contagious affection of the skin characterized by the development of vesicles, pustules, and other lesions on the skin, and caused by the presence of an animal parasite, known as the Acarus scabiei.
The affection usually commences by the appearance of small, non-umbilicated vesicles on the hands and between the fingers, accompanied with severe itching. The itching leads to scratching, and as a consequence transfer of the affection to other parts of the body with which the hands are brought in contact. Very early in the disease, then, we will find it appearing on the penis, on the breasts in women, and on the feet in children. From these parts it may spread over the greater part of the surface, more profoundly on the anterior than posterior parts and avoiding the face and scalp.
The vesicles above mentioned may be termed the primary lesions of the disease, but are usually followed in a few days by others secondary to the irritation produced by the insect, and to the effects of the finger nails. These new lesions may be papular or pustular in character, and may even assume distinctly eczematous characters, or develop into a true eczema in those predisposed to this affection. On the penis the lesions are usually papular. None of these features are absolutely pathognomic. There is, however, a lesion which is met with in no other disease, and which when found renders the diagnosis absolute. This is a fine, grayish line frequently terminating in a vesicle, and found between the fingers more frequently than elsewhere. It is called the acarian burrow. When an impregnated female acarus finds lodgment on the skin, she immediately seeks a place in which to deposit her eggs. This she accomplishes by boring beneath the epidermis and laying an egg, and then advancing in a straight or slightly curved line for several days until ovulation is complete. She then dies, and her decomposing remains give rise to a vesicle or pustule. When the eggs hatch, the young find their way to the surface, and as soon as they assume the adult form copulate, and the impregnated females commence to burrow as did their mother before them. A sharp needle-point, if guided by a sharper eye, will sometimes extract the acarus from her nest. The male acarus never burrows, and is very rarely detected.
