Skin Parasites

Scabies (Itch)

Scabies is a contagious disease due to infestation by the mite called the Acarus scabiei, which has its habitat in the human skin. The female, after fertilisation, burrows into the skin, while the smaller male soon dies. In the burrow the female lays her eggs at the rate of about 2 or 3 a day, which in their turn grow into adult mites and infest new areas. The adult is a small organism with legs and suckers, which is just visible to the naked eye as a pearly white speck. The disease is usually contracted from a bed-fellow, particularly by promiscuous persons, or from handling bedclothes infected by the acarus.

The eruption of scabies begins as a very small vesicle, frequently on the hands, feet, wrists and ankles, armpits, abdomen, breast and penis, which is followed by a small burrow reaching up to half an inch in length and causing great irritation, although this may not develop for about a month after infection. The irritation is generally severest at night. Scratching produces secondary excoriations and pustules.


The best treatment is to discard all clothing for disinfection, to apply benzyl benzoate 25 per cent application to cover the whole body, and allow to dry. Repeat twice, with 12-hour intervals. Twelve hours later, patients should have a bath, put on clean underwear, and change their sheets. Children only need half-strength benzyl benzoate application.

The itching generally ceases, and in most cases the disease is arrested, but occasionally some further treatment is required. To allay irritation, a zinc cream or an oily calamine lotion may be used on the skin. Severely infected patients must be kept in bed.


Pediculosis is a contagious animal parasitic affection, characterised by the presence of pediculi on the skin or hair of the body. They are small six-legged creatures without wings and are about 3 millimetres (1/6 inch) long. There are three varieties named according to the site they infest. They all cause great discomfort and itching, since they obtain their food by biting the skin and sucking out the blood.

The Head Louse (Pediculus capitis) is found on the scalp, and has a long oval greyish body with six legs furnished with nails; it has an oval head with two prominent eyes and two horns.

Nits are the eggs or ova. They are small whitish bodies which adhere to the hairs and look like small pieces of dandruff. One or two are deposited on a hair, and hatch out in from six to sixteen days.

The lice are most numerous on the sides and back of the head, and occur for the most part in school children brought up in unhygienic surroundings and are thence communicated to others. Lice cause extreme itching and scratching, so that often the irritation is unbearable and the sticky serum of the blood mats together the hair, forming crusts, or impetigo develops. Sleep is often interfered with and ill-health results. The lymphatic glands of the neck may become swollen or form abscesses from the scalp infection.

The Body Louse (Pediculus corporis) is generally found on the underclothing. It is somewhat larger than the head louse, and deposits its eggs in the seams of the clothing, remaining on the body only long enough to gain sustenance. The young are hatched in five or six days. The louse reproduces again in eighteen days.

The bite of the parasite is visible as a small red spot which produces extreme itching, and subsequent scratching results in long lines of excoriation. The chief locations for this parasite are the shoulders, back, chest, abdomen, buttocks and thighs. The middle-aged and elderly are more apt to be attacked than the young. Uncleanliness is again a prime factor in its occurrence. Typhus and other diseases are transmitted by the body louse where such infections are prevalent.

The Crab Louse (Pediculus pubis) is a smaller, shorter, stouter parasite than the two preceding types, and particularly attacks the pubes, but is also found in the armpits and over the eyelashes and beard of the male. They may be seen clinging closely to the skin with remarkable tenacity. The nits are attached to the pubic hair or the hair of other regions.

Crab lice occur on adults and produce the same lesions as the other varieties. This infestation is often the result of promiscuous sexual intercourse. In cases of pruritus ani and pruritus vulvx, these regions should be carefully examined for lice.


The main object in the treatment of these filthy diseases is the destruction of the parasite. The lesions they produce disappear with the disappearance of the lice, although some pigmentation of the skin may remain. The most effective drug for exterminating lice is DDT but its international danger is well known so other remedies, chiefly gamma benzene hexachloride (GBH) are often used. It need hardly be said that strict cleanliness of person is a sine qua non.

In the case of the head louse the simplest treatment for young children is to use a GBH shampoo or Prioderm lotion which contains malathion. The hair may be cut to get rid of the nits more easily. Hats must also be cleansed.

To get rid of body lice treatment must also be directed to the clothing, which needs to be changed often and baked, or treated with GBH, malathion, or another insecticide powder. This process is to be repeated until no more parasites are found.

After a hot bath, cresol solution, 2 per cent, or xylol, 25 per cent, in equal parts of lanolin and Vaseline, is also effective. The body hair should be shaved off.

The itching of the body is best allayed by carbolic acid lotion, one teaspoonful to a pint of water. DDT, 10 per cent, in water, is used for de-infesting clothes.

The crab louse may be destroyed by using a 25 per cent benzyl benzoate application. It must be persisted in till no more `crabs' are found and no itching is noticed.


Infestation with lice is now preventable by the use of dusting-powder or cream containing either GBH or malathion which may be applied to the body or clothes and will destroy the lice and prevent their breeding on the body.

Bed Bugs

Bed bugs are flat brown insects about 5 millimetres (ΒΌ inch) long, with an objection-able smell. They live in the crevices of wood-work and walls, and can live for many months without food.

The best preventives against these bugs are corrosive sublimate and pyrethrum powder. Purchase a small bottle of corrosive sublimate tablets (poison), usually sold at the chemists for surgical purposes, and dissolve one in a quart of water. This solution is to be used freely about the cracks of the bed, after it has been taken apart, and also about any wooden furniture of the room as well as the woodwork. The pyrethrum powder is then to be used freely. This process is to be repeated several times, since it is difficult to eradicate the bugs. Fumigation and DDT preparations are also used.

The bites themselves are best relieved by carbolic lotions, vinegar and water, ammonia and water, etc.


Some persons are much more susceptible to flea bites than others. Flea bites are visible as small red spots with a darker central spot. Animal fleas sometimes infest human beings, and rat fleas are carriers of bubonic plague infection.

Flea bites may be prevented by the use of oil of pennyroyal or by GBH. After bites have occurred, irritation is reduced by applications of weak carbolic acid lotion, or an ointment containing 2 per cent of carbolic acid, 2 per cent menthol, and 12 per cent coal tar solution.

GBH is efficacious in the destruction of fleas, and may be sprinkled in the clothing, but see under Louse Treatment.

Harvest Bugs, Wasps, Horse Flies, etc

Harvest Bugs (Chiggers). Harvest bugs may attack the legs or other exposed parts, their bites causing severe irritation. They may be warded off by DDT and the bugs may be removed from the skin by applying benzyl benzoate application or Lorexane cream.

Bees, Wasps and Hornets

The stings of these insects may give rise to considerable pain, and occasionally they may cause severe symptoms if they involve a blood vessel or occur on the tongue or mouth. Bee stings should be removed, and ammonia, or sodium carbonate or bicarbonate solution dabbed gently on. For wasp stings, lemon juice or vinegar alleviate the pain. For the bites of small gnats and midges, weak carbolic lotion relieves the irritation, or bites may often be prevented by using oil of lemon or 40 percent dimethyl phthalate cream on the skin. Use an antihistamine cream for severe reactions to bee stings or get medical attention.

Horse Flies and Mosquitoes

Treat as for midge; bathe with sodium bicarbonate lotion (a teaspoonful in half a pint of water); apply crotamiton lotion (Eurax).

Submitted By

Dr. Manun
The writer is a skin specialist practicing at Eskaton.

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