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Cellulitis                  SX  |  RX    |     Cellulitis2008.pdf                                                                                                                      

Cellulitis is an infection of the skin and subcutaneous tissue.      Images of Cellulitis    

Erysipelas is a clinical variant of cellulitis, is characterized by well-demarcated erythema, tenderness, and swelling, & discrete raised border.  Erysipelas usually affects the face, or the extremities.     Images of Erysipelas  

Facial Cellullitis & Erysipelas is suggested by a well-demarcated raised border cellulitis of the face.  Both preseptal & orbital cellulitis cause marked eyelid inflammation & swelling.  However, decreased visual acuity, decreased extraoccular eye movement, marked chemosis, pain on eye movement, or significant axial proptosis indicates orbital cellulitis, which can permanently damage the optic nerve as well as extend centrally and cause cavernous sinus thrombosis.

Image of Facial Erysipelas  

Necrotizing Cellulitis is a subset of soft-tissue infections marked by frank cutaneous & subcutaneous necrosis yet lacking involvement of fascial planes.  Its systemic toxicity is less than that of its more lethal cousin necrotizing fasciitis.
In immunocompetent hosts, GAS, Clostridium (gas forming anaerobes), Vibrio (seawater injury or seafood), Aeromonas spp. (outdoor freshwater injuries) may be the pathogens.  Gas-forming anaerobes, such as clostridia, Bacteroides, and peptostreptococci; Klebsiella & E.Coli can also produce a crepitant cellulitis.
In immunocompromised patients Pseudomonas aeruginosa can cause a cellulitis that may have a necrotizing component, ecthyma gangrenosum (EG).

SX:
It is marked by redness, tenderness, swelling, and a poorly defined border.  Fever, leukocytosis, lymphangitis, regional lymphadenopathy, hematogenous dissemination, and focal abscesses or bullae may accompany these infections.

Organisms:  
Overall, Group A beta-hemolytic streptococci (GAS), Strep. pyogenes, and Staphyloccal aureus account for most cellulitis.  Less common pathogens include group B, C, & G streptococci, Strep.pneumoniae, H.influenze, & Yersinia enterocolitica.  Other pathogens include enteric Gram-negative rods, Pseudomonas spp., & anaerobes.

RX:

For possible or proven MRSA Cellulitis:

PO Clindamycin 300-450 mg q6-8h, Trimethoprim-sulfamethoxazole (Bactrim/Septra-DS) 1 tab bid, or doxycycline (Vibramycin) or Minocycline 100 mg bid.
Rifampin has excellent activity against MRSA (not to be used alone due to rapid development of resistance) and may be used in combination with the other antibiotics.

* Fluoroquinolones should NOT be used to treat skin & soft tissue infections due to MRSA due to frequent resistant to Ciprofloxacin.

IV Vancomycin 30 mg/kg/24 hour in 2 divided doses (max not to exceed 2 g/24h).

IV Linezolid 600 mg q12h or daptomycin 4 mg/kg once daily.

For Nonfacial Cellulitis & Erysipelas:

• Incise & drain any abscess, and send the pus for Gram stain and culture.
• PO dicloxacillin or cephalexin  (Keflex) for 7-10 days with or without a single dose of IV Cefazolin (Ancef).
• IV Cefazolin (Ancef) single dose as outpatient, followed by daily home parenterial ceftriaxone (Rocephin) 50 mg/kg per day until significant improvement is noted, then completion of Rx with the above PO antibiotics.

For Facial Cellulitis & Erysipelas:

• All pts with moderate to severe nonperiocular facial cellulitis should initially be hospitalized to  monitor for progression to a necrotizing infection, which if not managed urgently by surgical debridement may result in significant facial disfigurement and dysfunction.   Obviously facial erysipelas should be treated with parenteral penicillin G 2 million units q4h.  Once the pts is afebrile for 24 hours, oral penicillin VK 500 mg q6h for 7-10 days will complete the Rx.
• Adults with established facial cellulitis should receive a parenteral semisynthetic penicillin as Nafcillin 1-1.5 g q4h or Cefazolin 1 g q8h until significant clinical improvement is noted; completion of Rx should include 7-10 days of oral dicloxacillin or cephalexin.
• Periocular soft tissue infections require thorough opthalmologic evaluation to distinguish preseptal from orbital cellulitis.  Moderate to severe preseptal cellulitis in older children & adults can progress to a necrotizing infection that requires urgent surgical debridement;  these pts should initially be treated with a parenteral semisynthetic penicillin as Nafcillin 1-1.5 g q4h or Cefazolin 1 g q8h until significant clinical improvement is noted.
• Orbital cellulitis, a medical emergency, should be managed initially with a parenteral semisynthetic penicillin as Nafcillin 1-1.5 g q4h and ceftriaxone (Rocephin).  Clindamycin may be substituted for the penicllin if anaerobic infection is suspected.  Orbital collections of pus must be drained immediately.  Otorhinoloryngologic consultation is indicated to help search for underlying sinusitis, which must be drained.  Close ophthalmologic follow-up is necessary to assess the response to treatment.

For Hand Cellulitis:

• Mild cellulitis be treated with arm elevation, splinting, and oral dicloxacillin or cephalexin;  penicillin, clindamycin, or metronidazole should be added if anaerobic on-infection is suspected.
• Severe hand cellulitis should be initially treated with parenteral nafcillin, oxacillin or cefazolin, arm elevation & observation until significant clinical improvement is noted.  All pus collections must be drained.  For human & animal bite infections of the hand, additional coverage against mouth anaerobes, Haemophilus & Pasteurella multocida, should be covered.

For Necrotizing Soft-Tissue Infections:

• Tissue necrosis mandates hospitalization and immediate surgical consultation for early complete debridement of necrotic tissue.  Bacteriologic evaluation of wound exudate, bulla fluid, excised tissue, and blood is essential. 
• Empiric parenteral vancomycin, gentamicin, and either metronidazole or clindamycin constitute an effective initial regimen.  Penicillin G at least 20 million units/day either alone or in combination with clindamycin or chloramphenicol should be instituted when crepitance or Gram stain indicates clostridial infection.

Ref:
Current Therapy in Adult Medicine 4th Ed, 1997 - Jerome Kassierer & Harry Greene II

2008