You think you can diagnose cellulitis?
Well, think again. Diagnosing cellulitis may be seemingly easy but it is fraught with pitfalls. Numerous studies show the misdiagnosis rate is over 30% (1, 2).
Cellulitis is a common skin infection and usually first evaluated by primary care, urgent care, or emergency department physicians. Many patients with presumed cellulitis are given empiric antibiotics and many are even hospitalized, leading to potential waste and unnecessary exposure to antibiotics for those misdiagnosed.
Common mimickers are:
- venous stasis dermatitis
- acute lipodermatosclerosis
- Erythema Migrans
- deep vein thrombosis
- gout
- lymphedema
- eczema
- Erythema Nodosum
- contact dermatitis
These conditions are collectively known as “Pseudocellulitis”
In addition, cellulitis is overwhelmingly unilateral. If you see bilateral redness and swelling, think again. It will not be cellulitis. Features that are NOT suggestive of cellulitis are:
1) bilateral or symmetrical presentation
2) lack of pain
3) mainly pruritic
4) long-standing with acute flares
5) progressive course
6) non-response to appropriate antibiotic therapy
Cellulitis misdiagnosis is common due to mimickers. Beware of “pseudocellulitis” and be sure antibiotics are appropriately given. One cannot diagnose what one does not know or remember. Make sure you keep a wider list of differential diagnoses when confronted with a red, painful, swollen limb.
(1) JAMA Dermatol. 2018: 154(4): 529-536.
(2) JAMA Demermatol. 2017; 153 (2): 141-146