Cellulitis refers to inflammation and infection of the tissues beneath the skin. The skin tissues in the infected area become red, hot, irritated and painful. Staphylococcus and streptococcus bacteria cause most cases of cellulitis in adults, and H. influenzae type B causes most cases of cellulitis in children less than 3 years of age, according to the American Osteopathic College of Dermatology. Bacteria enter the body through a break in the skin, and several factors can increase the risk for developing cellulitis.
Wounds
According to the Mayo Clinic, any type of wound that breaks the skin increases the risk of developing cellulitis because the injury gives bacteria an entry point into the body. Types of wounds include superficial wounds or wounds that occur on the surface of the skin, cuts, fractures, and burns. People who inject illegal drugs have a higher risk of developing cellulitis because the needle pierces through the skin, allowing for the bacteria to have a mode of entry into the tissues beneath the skin, notes the Mayo Clinic.
Weakened Immune System
The immune system recognizes foreign matter within the body, such as a virus or bacterium, and protects the body by fighting off the harmful agent. Certain medical conditions can decrease the immune system’s ability to defend the body, leaving a person more susceptible to acquiring infections, including cellulitis. According to MedlinePlus, conditions that can weaken the immune system include diabetes, leukemia, HIV or AIDS, chronic kidney disease, liver disease, and circulation disorders such as peripheral vascular disease. MedlinePlus notes that the use of corticosteroid medications can suppress the immune system's function as well.
Skin Disorders
Certain skin disorders increase the risk of developing cellulitis because they can cause cracks or open areas in the skin, reports the Mayo Clinic. Eczema causes inflamed, scaly or crusty patches on the skin. A type of fungus causes athlete's foot, which can lead to scaling and flaking of the affected foot. Chickenpox and shingles both cause blisters that eventually break open, resulting in a sore area on the skin. All these skin disorders have the potential to cause pruritus, or an intense feeling of itchiness. Breaks in the skin can also occur from the person scratching the affected area.
Chronic Swelling
A condition called lymphedema causes fluid buildup due to faulty lymphatic drainage, which causes chronic swelling in the arms or legs. The Mayo Clinic explains that the chronic swelling may cause the tissues to stretch and crack, which leaves the skin susceptible to the formation of a bacterial infection and cellulitis.
