Boils are bacterial infections of hair follicles and the surrounding skin that form pustules around the follicle. Boils are sometimes called furuncles. When several furuncles merge to form a single deep sore with several "heads," or drainage points, the result is called a carbuncle.
Boils are firm, red swellings about 5–10 mm across that are slightly raised above the skin surface. They are sore to the touch. A boil usually has a visible central core of pus; a carbuncle is larger and has several visible heads. Boils occur most commonly on the face, back of the neck, buttocks, upper legs and groin area, armpits, and upper torso. Carbuncles are less common than single boils; they are most likely to form at the back of the neck. Men are more likely than women to develop carbuncles.
As the infection that causes the boil develops, an area of inflamed tissue gradually forms a pus-filled swelling or pimple that is painful to touch. As the boil matures, it forms a yellowish head or point. It may either continue to swell until the point bursts open and allows the pus to drain, or it may be gradually reabsorbed into the skin. It generally takes between one and two weeks for a boil to heal completely after it comes to a head and
discharges pus. The bacteria that cause the boil can spread into other areas of the skin or even into the bloodstream if the skin around the boil is squeezed. If the infection spreads, the patient will usually develop chills, fever, and swollen lymph nodes. Red lines may appear on the skin running outward from the boil.
Boils and carbuncles are common problems in the general population, particularly among adolescents and adults. People who are most likely to develop these skin infections include those with:
- diabetes, especially when treated by injected insulin
- alcoholism or drug abuse
- recent experience of childbirth, especially women who are breastfeeding their babies
- poor personal hygiene
- crowded living arrangements
- jobs or hobbies that expose them to greasy or oily substances, especially petroleum products
- hair styles requiring frequent use of hair relaxers
- allergies or immune system disorders, including HIV infection
Causes & symptoms
Boils are most often caused by Staphylococcus aureus (staph), a bacterium that causes an infection in an oil gland or hair follicle. Although the surface of human skin is usually resistant to bacterial infection, staph can enter through a break in the skin surface, including breaks caused by needle punctures for insulin or drug injections. Hair follicles that are blocked by greasy creams, petroleum jelly, hair relaxers, or similar products are more vulnerable to developing boils. These bacterial skin infections can be spread by shared cosmetics or washcloths, close human contact, or by contact with pus from another boil or carbuncle.
Carbuncles are formed when the bacteria infect several hair follicles that are close together. Carbunculosis is a word that is sometimes used to refer to the development of carbuncles. The abscesses spread until they merge with each other to form a single large area of infected skin with several pus-filled heads. Patients with carbuncles may also have a low-grade fever or feel generally unwell.
Furunculosis is a word used to refer to recurrent boils. Many patients have repeated episodes of furunculosis that are difficult to treat because their nasal passages carry colonies of staph. Skin and anal colonization are fairly common as well. Persistent furunculosis may be an indication of a depressed immune system. A physician should be consulted if boils are a persistent problem in order to determine whether there is an underlying disease such as diabetes, HIV infection, or immune system disorders.
A diagnosis of boils is usually made on the basis of visual examination of the skin. For the most part, boils are not difficult to distinguish. A doctor can make a culture from pus taken from the boil to confirm the diagnosis and treatment. The patient's nasal discharge may also be tested. In cases of persistent recurrent boils, family members or close contacts may be examined to see if they are carriers of staph.
Patient education is an important part of the treatment of boils. Patients need to be warned against squeezing boils because of the danger of spreading the infection into other parts of the skin or bloodstream. It is especially important to avoid squeezing boils around the mouth or nose, because infections in these areas may be carried to the brain, although this happens rarely. Patients should also be advised about keeping the skin clean, washing their hands carefully before and after touching the boil, avoiding the use of greasy cosmetics or creams, and keeping their towels and washcloths separate from those of other family members.
The use of the following supplements is reported to be effective in treating boils: zinc, 45 mg per day; vitamin A, 50,000 IUs per day for two weeks; vitamin C,1 g three times per day; and beta-carotene, 100,000 IUs per day.
Taking the proper homeopathic medication in the first stages of a boil can bring about early resolution of the infection and prevent pus formation. The most likely choices are belladonna or Hepar sulphuris. If the boil has already formed, Mercurius vivus or silica may be recommended to bring the pus to a head.
A variety of herbal remedies can be applied topically to fight infection. These include essential oils of bergamot, Citrus bergamia; chamomile, Matricaria recutita; lavender, Lavandula officinalis; and sage, Salvia officinalis; as well as tea tree oil, Melaleuca spp. Application of a paste or poultice containing goldenseal root, Hydrastis canadensis, is recommended to help kill bacteria and to reduce inflammation. Washing the skin around the affected area with a mixture of goldenseal, Hydrastis canadensis, and witch hazel, Hamamelis virginiana, dissolved in warm water is also recommended.
Boils are usually treated with application of antibiotic creams, following the application of hot compresses. The compresses help the infection to come to a head and drain and are an important part of the treatment regime. Carbuncles and furunculosis are usually treated with oral antibiotics as well as antibiotic creams or ointments. The usual course of oral antibiotics is 5-10 days; however, patients with recurrent furunculosis may be given oral antibiotics for longer periods. Patients with bacterial colonies in their nasal passages are often given mupirocin ointment (Bactroban) to apply directly to the lining of the nose and should wash the area once a month with an antiseptic soap such as Phisohex.
Boils or carbuncles that are very large or that do not resolve may be opened with a sterile needle or surgical knife to allow the pus to drain. Surgical treatment of boils is often painful and usually leaves noticeable scars.
The increase of antibiotic- and biocide-resistant strains of Staphylococcus aureus has caused growing concern among doctors, as some of these strains are now resistant to disinfectants used to clean endoscopes and other surgical equipment. Resveratrol, which is a phytoalexin, or compound formed by plants at the site of a fungal or bacterial invasion, appears to be highly effective in treating boils and other skin infections in humans caused by S. aureus.
Boils usually drain or are reabsorbed in two or three days. Recurrent boils and carbuncles, however, are fairly common. In addition, although the spread of infection from boils is relatively unusual, there have been deaths reported from brain infections caused by squeezing boils on the upper lip or in the tissue folds at the base of the nose.
To minimize the risk of developing bacterial skin infections the skin should be kept clean; to avoid spreading the infection, washcloths, towels, and facial cosmetics should not be shared with others. A healthy diet should be maintained and allergic foods should be eliminated. This will ensure that the immune system will be supported, and that boils will be prevented.
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