Bullous Hemorrhagic Cellulitis

1) Ddx for bullous hemorrhagic lesions in this case:
Fairly broad, but basically broken down into:

a) Infectious - Bullous cellulitis, Necrotizing fasciitis, Bullous impetigo, Echthyma gangrenosum, menigococcemia (late stage), Staph Scalded Skin, Herpes, Zoster, Gas gangrene

b) Autoimmune - bullous pemphigoid vs pemphigoid vulgaris, pyoderma gangrenosum

c) Drug reaction (TEN and SJS), contact dermatitis

d) Other- including DVT and ischemia

2) Differentiating necrotizing fasciitis from cellulitis
- Extremely important as necrotizing fasciitis has high mortality, and requires immediate surgical exploration and debridement
- Clinically, nec fasc is characterized by rapid progression, severe systemic toxicity, pain out of proportion to exam, +/- gangrene and crepitus.  Presence of bullae and blisters should make you extremely worried about nec fasc.
- Imaging can be helpful - CT scan showing gas in fascial planes, also MRI, but if high clinical suspicion do not delay surgery
- Marked lab abnormalities in nec fasc - typically, very high WBC, +/- elevated CPK and inflammatory markers

- Laboratory Risk Indicator for Necrotizing Fasciitis (Critical Care Medicine 2004) - scoring system based on retrospective cohort, and subsequently validated
    i)  CRP > 15 mg/dL= 4 pts
   ii)  WBC 15-25 = 1 pt, >25 = 2 pts
   iii) Hb 11-13.5 = 1 pt, <11 = 2 pts
   iv) Na <135 = 2 pts
   v)  Cr > 1.6 = 2 pts
   vi) Glucose > 180 = 1 pt
    --> Score of 6 or more has high positive predictive value (92%) -- should strongly consider surgical exploration!!

3) Abx therapy of severe skin and soft tissue infections
- Must cover gram positive cocci - strep and staph. 
- Gram negatives - depends on situation, but generally if immunocompromised (like this pt with Diabetes and MDS), diabetic foot ulcers, in and out of hospital
- Other situational risk factors - Pseudomonas (burns, neutropenic, skin grafts, hot tub folliculitis, nail punctures), Vibrio vulnificus (salt water expoure or shellfish), Aeromonas (fresh water exposure), Pasteurella (animal bites), Captocytophaga (dog bites), Acinetobacter (travel to Iraq/Afghanistan)

--> for most hospitalized pts, Vancomycin is adequate, unless risk factors as above. 
  

4) Review bullous hemorrhagic cellullitis
- Fairly recently described entity (1990s), usually caused by Strep > staph > GNRs.  Often severe infection with high risk of progression to nec fasc.  Usually occurs in diabetics or other immunocompromised.   Recent case series in Thailand described 7 patients with bullous hemorrhagic cellulitis with similar presentation to our patient, with watery diarrhea, n/v, and severe abdominal pain.

(Ellen Eaton MD, 8/16/10)

(Chanu Rhee MD, 6/28/10)