Cellulitis is a bacterial skin infection that affects the deeper layers of the skin, including the dermis and subcutaneous fat tissue. This condition can occur anywhere on the body, but it most frequently develops in the lower legs, often affecting only one leg at a time. The infection begins when bacteria enter the skin barrier, leading to rapidly spreading inflammation.
The Distinct Visual Signs of Cellulitis
The most recognizable sign of cellulitis on the legs is a spreading area of redness, which can range from bright red to purple or brown discoloration on darker skin tones. This discoloration typically does not have sharp, distinct borders; instead, it tends to blend gradually into the surrounding healthy skin. The affected area often appears puffy or swollen due to fluid accumulation.
The swelling causes the skin to look taut, stretched, and often shiny or glossy across the leg. In more severe cases of swelling, the skin surface may take on a dimpled or pitted appearance, resembling the texture of an orange peel. Small blisters or fluid-filled spots may also develop on the skin’s surface as the infection progresses. Unlike some rashes, the changes caused by cellulitis are typically localized to one area that grows quickly, rather than presenting as scattered spots.
Accompanying Sensory and Systemic Symptoms
Beyond the visual changes, cellulitis causes a distinct sensory experience in the affected area of the leg. The skin will feel noticeably warm or hot to the touch due to increased blood flow and inflammation. Localized tenderness and pain are also common, which may feel like a throbbing or burning sensation that intensifies when the area is pressed or moved.
The infection is not limited to the skin and can cause systemic symptoms as the bacteria and inflammatory response spread. A person with cellulitis may experience flu-like symptoms such as fatigue and malaise. Systemic involvement is often indicated by the onset of fever and chills, and the lymph nodes in the groin area may become swollen and tender as they filter the spreading bacteria.
Common Causes and Risk Factors for Leg Cellulitis
Cellulitis is caused by common bacteria, most often Streptococcus or Staphylococcus species. These bacteria cause infection when they breach the skin barrier and enter the deeper tissues. The entry point is often a minor break in the skin, such as a small cut, scrape, insect bite, puncture wound, or a surgical incision.
The legs are particularly susceptible due to several risk factors that compromise skin integrity and circulation. Existing skin conditions that cause breaks, such as athlete’s foot, eczema, or chronic dry skin, provide easy entry points for bacteria. Conditions that lead to chronic swelling, like lymphedema or chronic venous insufficiency, can also weaken the skin and immune defenses in the lower limbs, increasing the risk for recurrent cellulitis.
Seeking Prompt Medical Evaluation
Cellulitis requires prompt medical evaluation and treatment. If you notice a spreading area of redness, swelling, and warmth on your leg, seeking care quickly is necessary to initiate therapy. Treatment involves a course of oral antibiotics, which must be taken exactly as prescribed, often for five to ten days, even if symptoms begin to improve sooner.
For more severe infections, or if the initial oral antibiotics are not effective, hospitalization may be required to administer antibiotics intravenously. It is important to monitor the infection by drawing a line around the border of the redness with a marker and dating it, which helps track if the infection is spreading. Red flags that require emergency care include a high fever, rapidly worsening pain, or the development of numbness or tingling in the affected leg, as these signs may indicate a deeper, more severe infection or progression toward sepsis.