Skin infections fall into three general categories: fungal, viral and bacterial. According to the Cleveland Clinic's Center for Continuing Education website, some of the most common bacterial skin infections include cellulitis, impetigo, folliculitis, furuncles, boils and carbuncles. Many kinds of bacteria live on the skin without causing any problem, a condition referred to as colonization. But when there is an opening in the skin caused by trauma of any kind, a portal of entry is created, allowing bacteria to migrate into tissues, carrying the potential for infection along with them.
Cellulitis
Cellulitis of the skin looks red and swollen, feels warm and is painful. The infection is potentially dangerous and can spread quickly without timely medical intervention. Most often seen on the lower extremities, cellulitis may be located anywhere on the body and is caused by several bacteria normally found on the skin, including streptococcus, staphylococcus and more recently, Methicillin Resistant Staphylococcus Aureus, or MRSA.
Impetigo
Impetigo is a contagious skin infection commonly seen in young children. Impetigo begins with red spots that blister and ooze a yellow colored, infectious material. When spots are finally drained dry, the substance forms a yellow crust. These sores are usually found around the nose and mouth, are not painful and resolve with medical treatment. The bacteria responsible for impetigo are most often caused by staphylococcus aureus and streptococcus pyogenes--organisms that are often colonized on the skin but become infectious when they enter the skin through a cut, scrape, or other injury resulting in skin disruption. Impetigo is treated with antibiotics and children are no longer considered contagious about 24 hours after antibiotic treatment begins.
Folliculitis and Furuncles
Folliculitis is an infection of the hair follicle, usually caused by staphylococcus. Infection of the hair follicle is typically found in or around beards, under the arms, or whereever hair is growing. There may be no signs and symptoms of infection with folliculitis; the condition may even go unnoticed. A furuncle, on the other hand, is a deeper continuation of folliculitis and appears as a red, painful nodule that ruptures and drains infectious matter.
Boils and Carbuncles
Boils and carbuncles are larger, deeper, infected nodules that originated in infected hair follicles, according to the Mayo Clinic website. They are very tender and may expand quickly. They are often filled with infectious material that eventually drains. Larger boils and carbuncles may need to be treated with oral and topical antibiotics to avoid progression to cellulitis.
