Are Boils Contagious?

A boil is a pus-filled localized skin infection.

A boil is a bacterial skin infection of a hair follicle.

• Boils contain pus.
• Boils are usually caused by staphylococcal bacteria.
• Boils are also known as furuncles.

There is some controversy about boils being contagious. Some experts say the boils themselves are not contagious because they can occur from bacteria normally found on the skin. Others, however, say that boils are contagious because it is possible for person-to-person transfer of bacteria if the infected boil touches the skin of another person, who then may also develop boils.

Although the most common range of the incubation period for staphylococci is about four to 10 days, boils caused by these bacteria that are normally found on the skin are considered to have a variable incubation period.

A boil begins when the skin turns red and tender in the area of the infection. After about four to seven days, the tender lump often starts to turn the skin whitish as pus collects under the skin. Some boils may spontaneously burst and leak out pus. Others may expand to form an abscess.

It is possible for boils to spread to another person if bacteria from the initially infected person contact the skin of another person who is susceptible to the infecting bacteria. However, a boil can spread in the skin of an infected individual to become an abscess or develop into a clump of boils (carbuncle).

Severe infections can lead to fever, lymph node swelling, and more severe complications of infection, such as sepsis.

Boils can be cured once the pus drains out of the boil and the infecting bacteria are eliminated. When this occurs, the symptoms of skin redness, swelling, and pain resolve after a few days. Some smaller boils that are not deep in the skin may spontaneously drain while others may require a physician to incise the boil so that pus can drain out.

Both topical antibiotics and occasionally oral antibiotics are given to eradicate infecting bacteria. Large boils may require gauze packing to help facilitate pus drainage. The gauze is usually removed in one or two days.

Individuals should seek medical care for boils if they start running a fever, have severe pain at the site of the boil, the boil doesn't drain, if other boils begin to appear, or if a red streak extends from a boil. Individuals with heart murmurs, immune system depression, diabetes, or those who are taking medicines that alter the immune system should contact their physician urgently if they develop a boil.