A boil is a circumscribed inflammatory process, caused by the entrance of pus producing germs into the skin either through the pores (the mouths of the sweat glands) or along the shafts of the hair, and in this way invading the glands which secrete a greasy material (sebaceous glands). In either case the pus germs set up an inflammation of the sweat or sebaceous glands, and the surrounding structures of the skin, and a small, red, itching pimple results. Rarely, after a few days, the redness and swelling disappear, and the pus, if any, dries and the whole process subsides. This is called a “blind boil.” But usually the boil increases in size for several days, until it may be as large as a pigeon’s egg. It assumes a bright red sharply defined, rounded shape, with a conical point, and is at first hard and then softens as pus or “matter” forms. There is severe pain of a throbbing, boring character, which is worse at night, and destroys the patient’s sleep and appetite. There may be some fever. The glands in the neighborhood may be enlarged and tender, owing to some of the pus germs’ escaping from the boil and lodging in the glands.

If the boil is not lanced, it reaches its full development in seven to ten days with the formation of a central “core” of dead tissue and some pus, which gives to the center of the boil a whitish or yellowish brown appearance. The boil then breaks down spontaneously in one or more places (usually only one) and discharges some pus, and, with a little pressure, also the white, central core of dead tissue. The remaining wound closes in and heals in a week or two. Boils occur singly or in numbers, and sometimes in successive crops. When this happens it is because the pus germs from the previous boils have invaded fresh areas of skin.

Causes. Boils are thus contagious, the pus germs being communicated to new points on the patient’s skin, or to that of another person. Local irritation of the skin, from whatever cause, enables the germs to grow more readily. The existence of skin diseases, as eczema (“salt rheum”), prickly heat, and other sources of itching and scratching, is conducive to boils, as the pus germs contained in ordinary dirt are rubbed into the irritated skin. Whenever the skin is chafed by rough clothing, as about the wrists and neck by frayed collars and sweaters, etc., boils are likely to occur. Also when the face and neck are handled by barbers with dirty hands or instruments, a fruitful field is provided for their invasion. While boils are always the result of pus germs gaining entrance to the skin glands, and, therefore, strictly due to local causes, yet they are more prone to occur when the body is weakened and unable to cope with germs which might do no harm under other circumstances.

The conditions favoring the occurrence of boils are: an impoverished state of the blood, errors of diet and indigestion, overwork, dissipation, and certain diseases, as typhoid fever, diabetes, and smallpox. Boils are thought to occur more frequently in persons with rough skin and with a vigorous growth of dark hair. They may be situated on any part of the body, but certain localities are more commonly attacked, as the scalp, the eyelids, cheeks, neck, armpits, back, and buttocks. Boys and young men are generally the sufferers.

Treatment. The importance of cleanliness cannot be overestimated in the care of boils if we keep their cause in mind. Dirty underclothes or fingers used in squeezing or otherwise handling the boil, may carry the trouble to fresh parts. Any sort of local irritation should be removed; also all articles of clothing which have come in contact with the boils should not be worn until they have been washed in boiling water. There is no single remedy of much value for the cure of boils, although pills of calcium sulphide (each one tenth grain) are commonly prescribed by physicians, every three hours.

The most rational measure consists in removing the general causes, as noted above, if this is possible. When the patient is thin and poorly nourished, give food and cod liver oil; and if the lips and skin are pale, iron arsenate pills (one sixteenth grain each) are to be taken three times daily for several weeks. A boil may sometimes be arrested by painting it with tincture of iodine until the boil is almost black, or with a very heavy coating of collodion. If a boil continues to develop, notwithstanding this treatment, one should either use an ointment of vaseline containing ten per cent of boric acid spread on soft cotton over the boil, or, if the latter is very painful, resort to the frequent application of hot flaxseed poultices.

When the boil has burst, and pus is flowing out on the surrounding skin, it should be kept very clean by frequent washing with hot water and soap and the application of a solution of corrosive sublimate (one part to 1,000) made by dissolving one of the tablets, sold everywhere for surgical purposes, in a pint of warm water. This will prevent the lodgment of the pus germs in the skin and the formation of more boils. Poultices mixed with bichloride (corrosive sublimate) solution are less likely to encourage inoculation of neighboring areas.

The poultices should be stopped as soon as the pain ceases, and the boil dressed as recommended above, dusted with pure boric acid and covered with clean absorbent cotton and bandage. After pus has begun to form in a boil recovery will be materially hastened by the use of a knife, although this is not essential. The boil should be thoroughly cleaned, and a sharp knife, which has been boiled in water for five minutes, is inserted, point first, into the center of the boil, far enough to liberate the pus and dead tissue. By this means healing is much more rapid than by nature’s unassisted methods. Pure carbolic acid, applied on the tip of a toothpick, thrust into the head of a boil, is generally curative. When many boils occur, consult a physician.