Boil

Boil or furuncle is a skin disease caused by the inflammation of hair follicles, thus resulting in the localized accumulation of pus and dead tissue. Individual boils can cluster together and form an interconnected network of boils called carbuncles. In severe cases, boils may develop to form abscesses. In general:


 * Furuncle
 * tender abscess arising in hair follicle with extension into deep dermis
 * almost invariably due to S. aureus infection
 * occurs in areas subject to friction and perspiration (neck, face, buttocks)
 * Carbuncle
 * deeper, interconnecting abscesses arising in contiguous hair follicles
 * commonly occurs at nape of neck and on back, thighs
 * a potential complication of furunculosis

Risk Factors

 * Chronic S. aureus carrier state (nares, axillae, perineum)
 * Obesity
 * Corticosteroid Rx
 * Diabetes
 * Defects in neutrophil function – uncommon

Symptoms
The symptoms of boils are red, pus-filled lumps that are tender, warm, and/or painful. A yellow or white point at the center of the lump can be seen when the boil is ready to drain or discharge pus. In a severe infection, multiple boils may develop and the patient may experience fever and swollen lymph nodes. A recurring boil is called chronic furunculosis.

In some people, itching may develop before the lumps begin to develop. Boils are most often found on the back, underarms, shoulders, face, lip, eyes, nose, thighs and buttocks, but may be found elsewhere. Boils on the ear tend to be more painful, and can create shooting pain in the entire area when touched.

Sometimes boils will emit an unpleasant smell, particularly when drained or when discharge is present, due to the presence of bacteria in the discharge.

Causes
Boils are generally caused by an infection of the hair follicles by Staphylococcus aureus or Staphylococcus epidermidis, a strain of bacterium that normally lives on the skin surface. It is thought that a tiny cut of the skin allows this bacterium to enter the follicles and cause an infection. This can happen during bathing or while using a razor.

People with immune system disorders, diabetes, poor hygiene or malnutrition (Vitamin A or E deficiency) are particularly susceptible to getting boils; however, they also occur in healthy, hygienic individuals, due to over scratching a particular area of the skin.

Hidradenitis suppurativa causes frequent boils and boils in the armpits can sometimes be caused by anti-perspirant deodorants.

The development of boils throughout the body is also a symptom of smallpox.

Boils can also be caused by not washing an area of the body, particularly the face, where two or more areas of skin cleft together, such as where the nose meets the cheek or where the ear meets the head. Boils formed in this manner often have a visible core of dirt that emerges when drained.

Treatments
Most boils run their course within 4 to 10 days. For most people, self-care by applying a warm compress or soaking the boil in warm water can help alleviate the pain and hasten draining of the pus (colloquially referred to as "bringing the boil to a head"). Once the boil drains, the area should be washed with antibacterial soap and bandaged well.

For recurring cases, sufferers may benefit from diet supplements of Vitamin A and E.

In serious cases, prescription oral antibiotics such as dicloxacillin (Dynapen) or cephalexin (Keflex), or topical antibiotics, are commonly used. For patients allergic to penicillin-based drugs, erythromycin (E-base, Erycin) may also be used.

However, some boils are caused by a super bug known as Community-Associated Methicillin-Resistant Staphylococcus Aureus, or CA-MRSA. Bactrim or other sulfa drugs must be prescribed relatively soon after boil has started to form. MRSA tends to increase the speed of growth of the infection.

Magnesium sulfate paste applied to the affected area can prevent the growth of bacteria and reduce boils by absorbing pus and drying up the lesion.

Acute Pharmacotherapies

 * If fever, carbuncles, recurrences -> systemic abx vs. S. aureus
 * Dicloxacillin 500 mg po q6h x 10-14 days
 * Alternatives:
 * cephalexin 250 mg qid
 * clindamycin 150 mg qid
 * Bactrim
 * Abx
 * Mupirocin 2% ointment to anterior nares bid x 5 days
 * Eliminates S. aureus nasal carriage for up to 90 days
 * Also effective against MRSA, but 40% recur on maintenance Rx
 * Rifampin 600 mg po qd x 10 days
 * Eliminates nasal carriage for up to 3 months
 * Consider in patients who have failed other preventive measures
 * Rx acute recurrence simultaneously w/dicloxacillin or alternative x 10d
 * Clindamycin 150 mg po qd x 3 months (suppressive regimen)
 * Shown in one study to decrease frequency of recurrence

Indications for Surgery

 * If persistent despite Rx -> incision and drainage

Prognosis
For most cases, there are no serious complications and a full recovery is expected.