Article: Cellulitis

Cellulitis is an inflammation of the connective tissue underlying the skin, that can be caused by a bacterial infection. Cellulitis can be caused by normal skin flora or by exogenous bacteria, and often occurs where the skin has previously been broken: cracks in the skin, cuts, burns, insect bites, surgical wounds, or sites of intravenous catheterinsertion. The mainstay of therapy remains treatment with appropriate antibiotics. It is unrelated to cellulite, a cosmetic condition featuring dimpling of the skin.

Symptoms

Cellulitis is characterized by redness, swelling, warmth, and pain or tenderness. Cellulitis frequently occurs on exposed areas of the body such as the arms, legs, and face. Other symptoms can include fever or chills and headaches. In advanced cases of cellulitis, red streaks (sometimes described as ‘fingers’) may be seen traveling up the affected area. The swelling can spread rapidly.

Causes

Cellulitis is caused by a number of types of bacteria entering by way of a break in the skin. This break need not be visible. Group A streptococcus and staphylococcus are the most common of these bacteria, which are part of the normal flora of the skin but cause no actual infection until the skin is broken. Predisposing conditions for cellulitis include insect bite, animal bite, pruritic skin rash, recent surgery, athlete’s foot, dry skin, eczema, burns & boils.

Risk factors

The elderly and those with weakened immune systems are especially vulnerable to contracting cellulitis. Diabetics are more prone to cellulitis than the general population because of impairment of the immune system; they are especially prone to cellulitis in the feet because their disease causes impairment of blood circulation in their legs leading to their having foot ulcers that commonly become infected.

Immunosuppressive drugs, HIV, and other illnesses or infections that weaken the immune system are also factors that make infection more likely. In addition, chickenpox and shingles often result in blisters which break, providing a gap in the skin which bacteria can enter through. Lymphedema, which causes swelling on the arms and/or legs, can also put an individual at risk.

Diseases that affect blood circulation in the legs and feet, such as chronic venous insufficiency and varicose veins, are also risk factors for cellulitis.

Cellulitis is also extremely prelevant amongst dense populations sharing hygiene facilities and common living quarters. Military instillations which require communal showers provide such an enviornment, as it is prelevant amongst many recruits going through boot camp, especially during United States Marine Corps indoctrination at Parris Island, South Carolina and during training at the United States Marine Corps Platoon Leaders Class in Quantico, Virginia.

Diagnosis

Cellulitis is most often a clinical diagnosis, and local cultures do not always identify the causative organism. Blood cultures usually are positive only if the patient develops generalised sepsis. Conditions that may resemble cellulitis include deep vein thrombosis, which can be diagnosed with a compression leg ultrasound, and stasis dermatitis, which is inflammation of the skin from poor blood flow.

Incubation

Cellulitis can develop in as little as twenty-four hours, or can take days to develop.

Duration

In many cases, cellulitis takes less than a week to disappear with antibiotic therapy. However, it can take months to resolve completely in more serious cases, and can result in severe debility or even death if untreated.

Treatment

If the case of cellulitis is minor, oral antibiotics may be all that are necessary. These are often intended to be taken for about ten days, and the patient usually sees his or her doctor after a day or two of taking the medication to ensure that it is working correctly. In addition, the doctor may instruct the patient to elevate the affected area. Antipyretics or anti-inflammatory drugs may also be used.

If the oral antibiotics do not work or if the patient has a high fever when he or she comes to see the doctor, intravenous (IV) antibiotics will most likely be necessary. IV antibiotics can be administered at a clinic, the hospital, or the patient’s home. The specific antibiotic prescribed will depend on the physician's assessment as to the most likely causative bacteria: usually Gram-positive organisms will be covered with an antistaphylococcal antibiotic, like flucloxacillin, and in specific situations Gram-negative organisms, anaerobic organisms, or specific species will be covered. If the infection forms an abscess, it may require surgical incision and drainage of the collected pus.

In the most serious cases, the cellulitis may spread to the bloodstream (causing septicemia) and other tissue, especially bone (causing osteomyelitis). In these cases, or where antibiotic therapy is unsuccessful, surgical debridement may be necessary.

In rare cases, secondary infections such as necrotizing fasciitis, where rapid necrotization of skin, fat, and connective tissue may necessitate surgical debridement of affected areas.

It is important to note that once an antibiotic is administered, the infection may initially get better for a period of hours and then take a turn for the worse as the bacteria are removed from the system. Close observation is recomended during this period as it may sometimes be assumed that the antibiotic is not working, when in fact it is.

Prevention

Good hygiene and good wound care lower the risk of cellulitis. Any wounds should be cleaned and dressed appropriately. Bandages should be changed daily or when they become wet or dirty will reduce the risk of contracting cellulitis. Medical advice should be sought for any wounds which are deep, dirty or if there is concern about retained foreign bodies.

Forms of cellulitis

A few of the forms of cellulitis are as follows: periorbital cellulitis (an infection of the eye socket), erysipelas, clostridial cellulitis, nonclostridial cellulitis, and synergistic necrotizing cellulitis (Pankey, 1992). A few forms of cellulitis do not have some of the symptoms most commonly listed (for example, clostridial and nonclostridial cellulitis do not cause the skin to turn red [Pankey, 1992]), but the majority do. Necrotizing fasciitis can be mistaken for cellulitis but is notable for involvement of the deeper tissue structures, the fascia, and can be limb and life threatening.