Cellulitis is a common bacterial infection affecting the deeper layers of the skin, specifically the dermis and subcutaneous tissues. It arises when bacteria, most often Streptococcus or Staphylococcus species, breach the protective outer layer of the skin. This entry leads to a localized infection, causing the affected area to become red, swollen, and tender to the touch. Left untreated, this infection can spread rapidly and potentially lead to serious complications.
Clarifying the Contagion Question
Cellulitis is generally not contagious and is not spread through person-to-person contact like a cold or the flu. The condition develops when the skin barrier is compromised, allowing bacteria that commonly reside on the skin’s surface to cause an infection internally. Transmission from one person to another requires a very specific and rare set of circumstances.
A theoretical risk of transmission exists only if an open wound on one person directly contacts the infected, open wound or pus of a person with active cellulitis. The infection is not airborne and cannot be spread by touching intact skin. For the infection to be passed, the bacteria must bypass the defenses of the recipient’s skin.
Recognizing Cellulitis and Entry Points
Cellulitis typically presents as an area of skin that is noticeably red, swollen, and feels warm. The affected area is tender or painful, and the discoloration may spread quickly. Systemic symptoms can include fever, chills, and swollen lymph nodes.
The infection begins when causative bacteria find an entry point into the body’s tissues. Common entry points include simple cuts, scrapes, puncture wounds, and insect bites. Skin conditions that cause cracks or breaks in the skin barrier also serve as bacterial pathways.
Vulnerabilities and Risk Factors
Examples of these vulnerabilities include cracked skin from athlete’s foot, eczema, dermatitis, or a recent surgical incision. Factors that increase susceptibility include a weakened immune system, chronic swelling of the limbs (lymphedema), and underlying conditions like diabetes.
Treatment and Monitoring Recovery
Cellulitis is primarily treated with antibiotic therapy. For most mild to moderate cases, a course of oral antibiotics, often lasting five to ten days, is prescribed. It is crucial that the full course of medication is completed, even if symptoms improve, to ensure the infection is fully eradicated.
If the infection is severe, rapidly spreading, or does not respond to oral medication, hospitalization may be necessary to administer intravenous (IV) antibiotics. Patients should monitor the affected area closely; a common method is drawing a line around the border of the redness to track whether the infection is spreading or receding. Patients should also elevate the infected limb to help reduce swelling and improve circulation.
If the redness continues to spread rapidly, if a high fever develops, or if the patient experiences signs of systemic infection like confusion or dizziness, immediate emergency medical attention is required. Most people begin to see improvement within 48 hours of starting antibiotics and achieve a full recovery in about seven to ten days.