Cellulitis and Erysipelas
Cellulitis
Cellulitis is a commonly occurring and frequently recurring infectious disease of the skin with both local and systemic features. It is characterized by erythema, warmth, swelling, and tenderness and affects both cutaneous and subcutaneous tissue. Although cellulitis occurs most commonly in the extremities, it can occur in any area of the body. Patients may be predisposed to cellulitis infections if they experience disruption of the cutaneous barrier (eg, leg ulcers, traumatic wounds, toe-web dermatoses, such as tinea pedis), are venous or lymphatically compromised (eg, venous insufficiency, being overweight, prior saphenectomy, prior pelvic radiation or malignancy, previous tibial fracture, pregnancy, filariasis), or have a previous history of cellulitis.
Cellulitis occurs when bacteria enter the epidermis through cracks in the skin (eg, abrasions, cuts, burns, insect bites, surgical incisions, or intravenous catheters) and is frequently caused by streptococci groups A and B and Staphylococcus aureus. It is infrequently caused by streptococci groups C and G, Pseudomonas aeruginosa, Aeromonas hydrophylia and Vibrio vulnificus (after exposure to fresh or seawater).
Clinical Features
Local
- Generalized swelling of involved area
- Macular erythema
- Warmth to the touch
- Tenderness in affected area
- Tender regional lymphadenopathy
- Abscess formation
- Lymphangitis
- In patients with lower-extremity cellulitis, presence of tinea pedis or psoriasis dyshidrosis
Systemic
- Fever
- Chills
- Myalgias
Not all patients with cellulitis display all the local and systemic reactions.
Diagnosis
Cellulitis is typically diagnosed by evaluating the appearance of the skin, without establishing microbial etiology. Cultures may be useful in patients who demonstrate systemic toxicity, do not respond to therapy, have unusual exposure (eg, water or animals), or have had previous cellulitis infections.
Cellulitis in certain areas, such as the face, may signify a dental or sinus infection. Cellulitis occurring near a joint may signify septic arthritis or osteomyelitis.
Treatment
Cellulitis treatment is largely dependent on the microbe causing the infection. Depending on the patient's condition, treatment will be either an oral or parenteral antibiotic. This includes penicillin, clindamycin, trimethoprim-sulfamethoxazole, cephalexin, clarithromycin and azithromycin. Vancomycin is used in patients with existing antibiotic allergies. Secondary abscesses are treated with incision and drainage.
Erysipelas
Erysipelas is a unique form of superficial cellulitis associated with a marked swelling of the skin that does not involve subcutaneous tissue. Although infants and the elderly are at particular risk, it can affect people at any age. People with skin ulcers, eczematous lesions, chronic fungal infections, local trauma, and venous or lymphatic compromise may be predisposed to erysipelas infections. Patients may experience recurring, persistent erysipelas infections. They are typically caused by group A streptococci, and, much less commonly, by S aureus, Streptococcus pneumoniae, enterococci, and a variety of gram-negative bacilli.
Clinical Features
Local
- Skin lesion with a raised border
- Localized pain
- Edema
- Erythema
- Indurated appearance
Systemic:
- High fever
- Prolonged rigors
- Confusion or mental status changes, particularly in elderly patients
Diagnosis
Because of its unique appearance, erysipelas is typically diagnosed by evaluating the appearance of the skin.
Treatment
Erysipelas is usually treated with penicillin or erythromycin. It can also be treated with intravenous cephalosporin. When methicillin-resistant S aureus is suspected, vancomycin is recommended.
