Originally published in The Ottawa Citizen February 29, 2004
Originally titled: “Common Skin Infections”

Bacterial skin infections are a common reason why people consult their family doctor. Each infection has its own specific treatment.

Cellulitis is a common and potentially serious skin infection that normally starts in areas where there is pre-existing skin damage. The skin becomes swollen, red and hot and has a poorly defined border. The area of redness (erythema) rapidly expands and creeps along the skin within hours.

Breaks in the top skin layer (epidermis) from cuts, surgical wounds, ulcerations or sores, crush injuries and fungal infections leave the underlying skin surface (dermis) vulnerable to bacterial infection. Group A streptococcus and staphylococcus aureus reside on the skin surface and protect it from other, more harmful bacteria. However, should these bacteria migrate under the skin, they can cause considerable damage.

Cellulitis commonly occurs on the fingers and legs. Other regions include the face, feet, hands, torso, neck, buttocks and normal appearing skin.

Bacteria can also spread under the skin through the lymphatic channels. These channels are designed to return excess tissue fluid (lymph) back into the blood stream. This “tracking” appears as red streaky lines about half a centimetre wide, emanating from the infection site, and helps diagnose cellulitis.

If diagnosed early, treatment consists of an oral antibiotic. Intravenous antibiotics are used if oral treatment fails or if there is an initial extensive spread of the infection. Diabetics and people with compromised immune systems may require more aggressive treatments. Most infections respond within 24 hours but it may take up to three days for some who require intravenous antibiotics.

Periorbital (around the orbit of the eye) cellulitis is treated with oral antibiotics, hot compresses and close physician follow-up. Children who develop this infection often have a bacterial sinus infection. Should this infection work its way inward into the orbit, it can cause severe eye damage, an emergency requiring an assessment by an ophthalmologist.

St. Anthony’s fire or erysipelas is an angry red infection caused almost exclusively by beta-hemolytic streptococcus. Flu-like symptoms can occur prior to the infection’s appearance. The infected area has well-defined sharp raised borders. Tracking may be seen as well. Unlike cellulitis, most cases occur on normal intact skin, particularly on the legs and face. The incidence of erysipelas continues to increase. Young children, the elderly, persons with diabetes, alcoholics and immuno-compromised patients seem to be the groups most affected.

Impetigo is the “day care/child care infection.” It is contagious and easily spread by skin-to-skin contact. Children two to five years of age are the most likely to develop impetigo on wounds, cold sores and on cracked skin overlying the corners of the mouth. There are two types of impetigo: bullous (large blisters) and nonbullous. The latter type is seen most often and is caused by staphylococcus aureus and group A streptococcus. Small solitary or clustered sores, or pus-filled tiny blisters or vesicles, appear with honey-yellow fluid oozing from them. The fluid dries, forming a crust over the wound.

Bullous impetigo, a staphylococcus aureus-mediated infection, appears as two- to five- centimetre balloon-like blisters containing thin yellow fluid. The blister often ruptures and exposes a bare pink area of skin. A particular strain of staphylococcus aureus can produce a toxin causing a large area of the top skin layer to peel away. The infected area resembles a hot water burn, hence the name Scalded Skin Syndrome.

For single eruptions or small clusters of impetigo, topical application of the antibiotic creams mupirocin (Bactroban) or fucidic acid (Fucidin) can control and cure the outbreak. When washing the skin, do not vigorously rub or scrub it because it can spread the infection. Extensively spreading impetigo requires an oral antibiotic. Recurrent impetigo occurs on people who tend carry staphylococcus aureus in their nose. This carrier state can be reduced by the topical application of mupirocin twice daily for five days.

Skin abscesses or furuncles appear as painful red pus-filled masses arising from a hair follicle. They can appear anywhere on the body, especially on areas exposed to friction. Furuncles rarely appear before puberty. They typically break open on the skin surface, allowing the pus to drain from the wound. Application of hot compresses and topical antibiotics such as Fucidin or Bactroban can help the healing. Furuncles can also heal spontaneously or your doctor may have to incise it allowing it to drain and heal.

Clusters of furuncles (carbuncles) can form painful, large, swollen, red and deep abscesses that open and drain onto the skin surface. Fever and malaise may occur with these lesions.

Treatment usually consists of incision and drainage. The honeycombed pus-filled spaces within the carbuncle are broken down with an instrument called a hemostat. The open wound is packed with a sterile gauze strip to allow the wound to drain. Oral antibiotics are used for severe infections.

Prompt assessment by your doctor can help prevent the more severe forms of these infections. Consult your doctor if your are unsure what to do next.

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© Dr. Barry Dworkin 2004