Cellulitis: Skin Infection Causes, Symptoms, Treatment



What is Cellulitis?

  • Cellulitis is a common bacterial skin infection

  • Over 14 million cases occur in the United States annually

  • It is an acute bacterial infection that causes inflammation of the deep skin tissue and surrounding subcutaneous tissue.

  • This specific infection is without an abscess or purulent discharge

Cellulitis Causes

  • Most common cause: group A Streptococcus or group A strep

  • Skin is a protective barrier that prevents microbial pathogens from reaching the deeper skin tissues

  • When skin breaks due to injury, cut or any other reason, bacteria that lives in the skin or other bacteria enter and invade into the body system

Bacteria Enters through the Breaks in the Skin

  • Skin injuries: cuts, insect bites, animal bites, tattoos, piercings, ulcers

  • Fissures between toes

  • Intravenous site puncture, IV drug use

  • Surgical incisions

  • Chronic skin conditions: eczema, athlete’s foot

  • Chickenpox and shingles

Risk Factors for Cellulitis People with the following conditions are at the higher risk for getting cellulitis:

  • Being overweight

  • Diabetes mellitus

  • Peripheral arterial disease

  • Venous insufficiency

  • Chronic edema: swollen limbs (feet, legs, hands, arms)

  • Lymphedema: problems with lymphatic system that does not drain properly

  • The lymphatic system is part of the body’s immune system that move fluid that contains infection fighting cells throughout the body

  • Coronary artery bypass grafting: use healthy vein from the leg and connect to the coronary artery to improve blood flow to the heart


Cellulitis Symptoms

  • Appears as a red, swollen, and painful skin area that is tender and warm to the touch

  • It may look like pitted peel of an orange or blisters on the affected skin

  • If the infection is severe, people can have fever, chills, fatigue and generalized malaise.

  • Most common location of cellulitis is on the feet and legs, but it can happen in the anywhere in the body

  • Always check whether you have a proper sensation to touch and temperature on the affected skin

  • Cellulitis can spread and expand

Cellulitis Treatment

  • Cellulitis must be treated with antibiotics

  • If a person does have localized cellulitis without any signs of fever or chills, oral antibiotics will be used. The duration is usually 5 days.

  • If cellulitis is purulent, colonized by methicillin-resistant staph aureus (MRSA), abscess or extensive puncture wounds, or a history of IV drug use, different kinds of oral antibiotics are used and duration will be determined based on the patient’s improvement.

  • If a person has severe infection with signs of fever or chills, typical oral medication treatment is failed, immunocompromised or immunosuppressed (i.e. people with cancer, underwent chemotherapy), cannot eat oral medication, or has cellulitis overlying or near indwelling medical device (i.e. hip replacement, knee replacement), he or she must be admitted to the hospital and treated with IV antibiotics medication.

Cellulitis Complications

  • Complications are uncommon, but the serious infections can occur at the following locations:

  • Blood (bacteremia)

  • Vein swelling due to blood clots form close to the skin (thrombophlebitis)

  • Joints (suppurative arthritis)

  • Bone (osteomyelitis)

  • Lining of the chambers of the heart and heart valves (endocarditis)

  • Necrotizing fasciitis: must be treated immediately


Cellulitis Prevention

  • Cellulitis can occur more than once.

  • People do not develop immunity against the cellulitis.

  • There are no vaccine to prevent cellulits or group A streptoccus infection

Good Wound Care

  • Minor cuts:

  • Clean all minor cuts and injuries that break the skin (i.e. blisters and scrapes) with soap and water.

  • Clean and cover draining or open wounds with clean, dry bandage.

  • See a doctor for puncture and other deep or serious wounds

  • Open wound or active infection

  • Avoid hot tubs, swimming pools, natural bodies of water (i.e. lakes, rivers, oceans)

  • Wash hands with soap and water

  • Or, use alcohol-based hand rub if washing is not possible

  • Multiple cellulitis

  • Fungal infection can happen if multiple skin-related infections occur below the knee (i.e. athlete’s foot).

  • These fungal infections must be treated since they cause breaks in the skins that lead to recurrent cellulitis.

  • Diabetic foot

  • People with diabetes should check their feet daily.

  • They should look for injuries, wounds or signs of infections


References

  1. Brown BD, Hood Watson KL. Cellulitis. In: StatPearls [Internet]. StatPearls Publishing; 2021.

  2. National Center for Immunization and Respiratory Diseases, Division of Bacterial Diseases. Cellulitis. Centers for Disease Control and Prevention.