Randy Jacobs, M.D. Patient Education

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Skin Infections




What is a skin infection?


One of the functions of healthy skin is to protect your body from bacteria like staph or strep. But a scratch, cut, insect, or pet bite, picking with your fingernails, or even too much hand washing can produce a scrape or break in the skin. When enough harmful bacteria find their way into the scrape or break, the result is a skin infection.


Are there symptoms?


Sometimes. You may not notice any symptoms or you may have one or more of the following: Redness or warmth, swelling, pain, itching, burning, fever.


Are skin infections contagious?


Bacterial skin infections are contagious to a degree, so your doctor may recommend precautions. For example, avoid touching sores (especially scratching). This can cause the infection to spread to a wider area or to another part of your body. Infection can also spread to other persons from direct contact or indirectly from clothing, towels, bed linens, dishes or toys. Washing these items in soap and hot water helps prevent the spread of infection. And, of course, good personal hygiene will also protect others from the infection, especially in cases of impetigo.


What are the most common skin infections?


Wounds and lacerations. A break or tear in the skin that becomes infected. Wounds are usually caused by a blow or a sharp object. Lacerations are torn or jagged wounds and are frequent sites of infection.

Impetigo. A very contagious infection of the skin surface. Impetigo is most common in children. It starts as a runny blister on the face or hands and develops into an infected sore with a honey-colored crust.

Folliculitis. An infection at the hair follicle on the skin. It looks like a pimple and is aggravated by perspiration.

Furuncle. A boil that develops at the root of the hair follicle. This is hard, red bump that is painful to touch.


Cellulitis. A painful infection of the deeper layers of the skin. Usually on the foot or leg. The infected area is red and swollen. There may be fever.


Please tell me more about cellulitis?

As explained above, there are various types of bacterial infections of the skin. What you have is called cellulitis, which is just a fancy name for an infection in the tissue just under the skin that causes inflammation. This infection usually, but not always, follow some lesion in the skin that you may have noticed. This lesion may be a result of trauma, such as a cut or puncture, or a preexisting problem in the skin such as a pimple or ulcer. Often, if it begins in normal skin, it does so in the presence of edema, or swelling, of the area. It begins with redness and tenderness in the skin around the wound within several days after wounding yourself. This may be accompanied by a flu-like sensation, chills and fever.


Cellulitis is caused by a variety of bacteria but most commonly by one called Streptococcus pyogenes. Some other bacteria that occasionally cause cellulitis include Hemophilus Influenza and Staph Aureus. These bacteria cause an infection around the wound by being deposited into the tissue under the skin. After gaining access to the tissue under the skin the bacteria grow and reproduce which produces a response by the body's immune system. This response includes infiltration of the area with white blood cells, dilation of the blood vessels, and leakage of fluid from the vessels into the tissue. This produces the swelling, tenderness, and redness you experience.


Cellulitis can vary in its progression from the original mild redness. The redness may spread slowly without other symptoms or spread rapidly with fever and a feeling of sickness. The area of redness then becomes swollen and when pressed on leaves a pit behind. Sometimes a bump can form in the center of the involved area which can have a blister-like bump on top of it that is filled with involved area. These streaks represent an inflammation of the lymph vessels that carry fluid out of tissues. The infection can spread through these lymph vessels to the nearest lymph nodes and cause these to become swollen and tender.


If left untreated, cellulitis can cause a variety of problems, some quite serious. Abscess may occur in the area of the cellulitis. An abscess is a collection of pus in a cavity created by destruction of tissue. Also, patches of skin over the involved area may die. Worst of all, however, is that the bacteria causing the cellulitis may invade the bloodstream and cause what is known as septicemia. Death from septicemia may occur within 36 hours of the original injury.


Cellulitis is diagnosed by its clinical features. As stated above, these includes redness, tenderness, swelling, and warmth. It is difficult to determine the exact organism causing cellulitis in the majority of cases. By sticking a needle into the cellulitis and aspirating some fluid out and culturing it, and organism is found in only 25 percent of cases. For this reason an aspiration is rarely done. However, if the patient is ill in the hospital, then blood is drawn and cultures to make sure the bacteria hasn't spread to the blood. If it has, then the exact bacteria can sometimes be determined.


Cellulitis and other bacterial skin infections are treated with antibiotics, which are chosen by what your doctor thinks is the cause. If the infection is more severe, then the antibiotic is given intravenously in the hospital. Other antibiotics are used if the more rare causes of cellulitis or other bacterial skin infections are suspected. If the infection involves an arm or leg, in addition to antibiotics, the limb should be immobilized and elevated to decrease the swelling. A cool, wet dressing may be placed on the area to decrease the pain, then, followed by moist heat to help cause localization of the infection. With the above treatment, cellulitis and other bacterial skin infections can usually be successfully treated leaving no signs of infection.


Therapeutic Guidelines


Activity: Stay in bed or at complete rest in a chair until the fever is gone and until the pain, redness and swelling have greatly improved. Raise the affected part, if possible (Examples: Raise the foot of the bed if the area involved is in the foot of leg. Prop the arm on a pillow if the hand or arm is affected.)



Medications: Your medicines must be fitted to your own particular needs. Do not take any medicines (not even medicine you buy without prescription) without telling your doctor. If drugs are prescribed, carefully follow the instructions on the label. Please take the prescribed medication as long as the doctor has prescribed. Antibiotics may be needed for 4 or 5 days after all signs of infection have subsided.




          -  Temperature over 102^ F.

          -  Onset of chills within 24 hours after treatment has started.

          -  Drowsiness or lethargy.

          -  Pain not controlled by prescribed medication.

          -  Nausea, vomiting, or diarrhea.

          -  Recurrence of symptoms after treatment.