Encyclopedia of Health and Medicine

C
callus An accumulation of keratocytes that form
a thickened area of SKIN in response to repeated
friction or pressure, typically at the site of
repeated blistering. A callus may be a different
color than the surrounding skin, often grayish or
yellowish. Calluses are most likely to develop on
the palms, fingers, fingertips, heels, and balls of
the feet. Most calluses are not painful and help
protect the skin from blisters and other frictionrelated
injuries. Calluses do not require medical
intervention unless they cause PAIN. Applying aloe
or a moisturizing skin lotion and gently rubbing
the callus with a pumice stone while in the
shower or bath are measures that can contain the
size and thickness of calluses. Wearing gloves to
protect the hands and well-fitting socks to protect
the feet can help prevent a BLISTER and resulting
callus from forming.
See also CORNS; KERATOCYTE.
carbuncle Clusters of infected HAIR follicles
(furuncles) that often form an ABSCESS. Carbuncles
are most common on the back of the neck and
shoulders, though may form at other locations
where furuncles tend to occur. Carbuncles are
painful and often result in FEVER and general
malaise (not feeling well). The INFECTION is deep
within the layers of SKIN and generally requires
treatment with an oral ANTIBIOTIC MEDICATION. The
doctor may choose to lance (open with a sterile
incision) the carbuncle to allow the collected pus
to drain. Applying warm, moist compresses four to
six times a day helps open the follicles and allow
continued drainage as HEALING takes place.
Though poor PERSONAL HYGIENE can contribute to
the development of furuncles and carbuncles, the
primary cause of these painful sores is BACTERIA,
typically Staphylococcus, that normally resides on
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the skin. Carbuncles tend to recur. People who
have DIABETES are more likely to develop carbuncles
because the diabetes damages the delicate
blood vessels responsible for peripheral circulation,
preventing the bloodstream from carrying
bacteria-fighting blood cells to the site of the
infection. People who have impaired immune
function are also at increased risk. Untreated carbuncles
can result in scars after healing or can
progress to systemic infection (SEPTICEMIA).
See also CELLULITIS; FURUNCLE; SCAR.
cellulitis INFLAMMATION of the inner layers of the
SKIN and the underlying connective tissues, usually
the result of a bacterial INFECTION. People who
have PERIPHERAL VASCULAR DISEASE (PVD), DIABETES,
or other health conditions that impair BLOOD circulation
have increased risk for cellulitis. Cellulitis
develops when a break in the skin, such as a cut
or an insect bite or sting, allows BACTERIA normally
present on the surface of the skin to enter and
establish infection. The offending breach often
comes from something so small as to appear
insignificant until infection sets in. Staphylococcus is
the most common type of bacteria responsible for
cellulitis; Streptococcus is sometimes responsible.
Bacteria also may enter via contamination of a
penetrating object such as a splinter. Cellulitis
requires prompt treatment with ANTIBIOTIC MEDICA-
TIONS to minimize tissue damage and prevent the
spread of infection.
Symptoms and Diagnostic Path
Swelling, redness, and PAIN or itching are the key
symptoms of cellulitis. The edges of the infection
are diffuse, often making it difficult to establish a
border between healthy and infected tissue. The
doctor diagnoses cellulitis primarily on its appear-