Any break in the skin can develop infection. And to mountain bike is to break the skin.
Infection in a wound is usually due to bacteria. The most common are streptococcus
("strep") and staphylococcus ("staph"). Infection can be local
("cellulitis"), streaking ("lymphangitis" or "blood
poisoning"), or pus-forming ("boil" or abscess). The most dangerous
infections occur in wounds where there is dead tissue -- for example gas gangrene and
This boy stuck a needle into a burn blister on his
palm yesterday. Note the redness and the streaking.
||Lymphangitis is a streaking infection. Look for a red band going upstream
the wound. This infection is usually caused by strep, often in combination with staph.
This girl waded barefoot through a mountain stream, cutting the
bottom of her foot on broken glass. The wound is now more painful. See the small red
streaks heading around the foot. Lymphangitis always goes towards the heart.
|This is a "pustule." This type of infection occurs when germs
grow between the skin layers, raising up a "blister" of pus.
biker got a "puncture weed" in his shoe yesterday. Today there's a pustule on
the bottom of his foot. And can you see the slight pink streak heading across the
underside of the arch of the foot?
||"Cellulitis" is local infection without streaking. It's painful,
red, and swollen.
This girl borrowed biking shoes that were
too small. After wearing a hole in her toe, she did nothing to protect the wound. Today,
the toe is swollen, tender, pink, and oozing.
Infection can result from a foreign body in a wound.
biker ran a puncture-weed thorn into his thumb tip during a fall over a week ago. It's
still sore, and the puncture wound won't heal. Notice the whitish bulge between the
thumbnail and the wound. This is a foreign body infection. A wound that refuses to heal is
often contaminated or infected.
||A "boil" is a small abscess or collection of pus just under the
skin. When they occur without a wound, it's usually due to bacteria in a hair follicle
breaking out into the fatty tissue. It often happens in an area of chafing.
This biker has a boil at the belt line, caused by riding with
pants that were stiff and rubbed the skin.
|Not all infections are bacteria. Fungi and viruses can also infect wounds.
This young woman had a tiny cut on her finger. Her boyfriend had
a cold sore. When the cut seemed almost healed, it suddenly erupted with many painful
pustules. This is a herpes simplex (cold sore virus) infection of the skin.
Before antibiotics, infection in a wound was often fatal. All infections should be seen by
the doctor. (Some patients might choose to treat a small pustule without underlying
infection at home: remove the "roof" of the pustule, clean with Betadine, remove
any splinter or other foreign body, warm soak, and follow closely.)
See the doctor for any significant soft tissue infection, as soon as possible.
[First Aid Index Page]