- Clinical features
- Differential diagnoses
- This is commonly used to indicate a non necrotizing inflammation of the skin and subcutaneous tissues.
- The process is usually related to acute infection that does not involve the fascia or muscles.
- Cellulitis has been classically considered to be an infection without formation of abscess (nonpurulent), purulent drainage, or ulceration.
- At times, cellulitis may overlap with other conditions, so that the macular erythema coexists with nodules, areas of ulceration, and frank abscess formation (purulent cellulitis).
- Cellulitis usually follows a breach in the skin, such as a fissure, cut, laceration, insect bite, or puncture wound.
- In some cases, there is no obvious portal of entry and the breach may be due to microscopic changes in the skin or invasive qualities of certain bacteria.
- Organisms on the skin and its appendages gain entrance to the dermis and multiply to cause
- The vast majority of cases of cellulitis are likely caused by Streptococcus pyogenes and, to a lesser degree, by Staphylococcus aureus
- In rare cases,it results from the metastatic seeding of an organism from a distant focus of infection, especially in immunocompromised individuals such as;S pneumonia and marine Vibrio species.
- Neisseria meningitidis, Pseudomonas aeruginosa, Brucella species, and Legionella species have also been reported as rare causes of cellulitis resulting from hematogenous spread.
- Certain host factors predispose to severe infection
Chronic liver disease
Peripheral arterial disease
Chronic kidney disease
- Human, dog, cat, and wild-animal bites all predispose to cellulitis with unique pathogens.
- The patient may or may not relate an episode of
trauma that preceded symptoms; when cellulitis develops, it is usually several days after the inciting trauma.
- Rapid progression or significant pain is a concerning sign that may indicate a severe problem, such as necrotizing fasciitis.
- Hx of presence of other skin disorders, including various types of dermatitis and especially any preceding fungal infection, which may serve as a portal of entry for bacterial pathogen.
- PMHx;presence of comorbid conditions that may increase the risk for cellulitis, with the most common ones being diabetes mellitus,human immunodeficiency virus (HIV) infection/acquired immunodeficiency syndrome (AIDS), chronic kidney disease, and chronic liver disease.
- The surgical history may include a recent procedure that resulted in wound infection.
- Nonpurulent cellulitis is associated with 4 cardinal signs of infection:
- The involved site is the leg, which is the most common site
- Regional lymphadenopathy maybe present.
- Malaise, chills, fever, and toxicityare present
- Cellulitis characterized by violaceous color and bullae suggests more serious or systemic infection with organisms such as Vibrio or S pneumonia
- Signs/symptoms of potentially severe deep soft-tissue infection. Violaceous bullae Cutaneous hemorrhage Skin sloughing Skin anesthesia
Gas in the tissue
- Burn Wound Infections
n Necrotizing fasciitis
- Insect Bites
- Lymphoma, Cutaneous T-Cell
- Mycosis Fungoides
- Stevens-Johnson Syndrome
- No workup is required in uncomplicated cases of cellulitis that meet the following criteria: Limited area of involvement Minimal pain
No systemic signs of illness (eg, fever, chills, dehydration, altered mental status, tachypnea, tachycardia, hypotension)
No risk factors for serious illness (eg, extremes of age, general debility, immunocompromised status
- Antibiotic regimens are effective in more than
90% of patients.
- However, all but the smallest of abscesses require drainage for resolution, regardless of the microbiology of the infection.
- Cellulitis without associated purulent drainage or abscess (nonpurulent cellulitis)
- Outpatient treatment recommendations are as follows:
Dicloxacillin 500 mg PO q6h Cephalexin 500 mg PO q6h
Amoxicillin/clavulanate 500 mg/125 mg PO q12h
- Clindamycin 300 mg PO q6-8h
- Patients with severe cellulitis require parenteral
n Ceftriaxone, nafcillin, or oxacillin
- Antimicrobial options in patients who are allergic to penicillin include clindamycin or vancomycin
- Mammalian bites
- Should be treated empirically with antimicrobials that target anaerobic bacteria in addition to the common cellulitis pathogens.
- Outpatient; Amoxicillin-clavulanate, fluoroquinolone plus clindamycin or
trimethoprim-sulfamethoxazole (TMP-SMX) plus metronidazole.
- Inpatients can be treated with IV ampicillin-sulbactam or piperacillin-tazobactam.OR
ceftriaxone & metronidazole
- Urgent consultation with a surgeon should be sought in the setting of ; Crepitus Circumferential cellulitis Necrotic-appearing skin (bronzing) Rapidly evolving cellulitis
Pain disproportional to physical examination findings, severe pain on passive movement, or other clinical concern for necrotizing fasciitis.