Defining Cellulitis

Defining Cellulitis

Skinmed. 2007 Nov-Dec

Lawrence Charles Parish, MD; Joseph A. Witkowski, MD

Exactly what does cellulitis mean? How many consultation requests state that the patient has cellulitis, when, in fact, it was stasis dermatitis from which the patient suffered? Leider and Rosenblum, 1 considered the 20th-century lexicographers for dermatology, wrote:

Cellulitis literally means inflammation (-itis) of the little cells (cellul-). What is really meant, of course, is diffuse inflammation of parenchyma without necrosis or sharp localization of pus.

The definition given by the Microsoft Word dictionary is less precise but more limiting as describing cellulitis as “infection and inflammation of the tissues beneath the skin.”We have traditionally considered cellulitis to be inflammation in the dermis with both redness and induration present. No purulent opening can be seen; when there is a portal for pus, a furuncle or boil would be the diagnosis.

Cellulitis and Erysipelas

The terms cellulitis and erysipelas connote a diffusely spreading bacterial infection, excluding such walled-off lesions as the abscess, furuncle, and carbuncle (ie, not a boil). The pathology of erysipelas ( Figure 1 ) should be limited to the upper portions of the dermis, while cellulitis ( Figure 2 , Figure 3 ) seeks the lower portions of the dermis and the subcutaneous tissue. Because the clinical pictures often blend, many Northern European physicians use the term erysipelas to include both erysipelas and cellulitis. Unfortunately, both terms get bantered about in the United States, creating a continuing state of confusion. There seems to be a movement to discard the concept of erysipelas entirely. 2–5

Both conditions represent the results of pyogenic infections due to such bacterium as β-hemolytic streptococcus, group A, B, C, or G. Sometimes Staphyloccocus aureus is implicated in cellulitis, while Haemophilus influenzae type b can cause childhood cellulitis. Rarer causes of cellulitis include Aeromonas hydrophila, 6 Vibrio alginolyticus, 7 and Pasteurella multocida. 8 Erysipelas, once called phlegmona diffusa, and cellulitis can develop due to Pseudomonas aeruginosa, Streptococcus pneumoniae, Serratia marcescens, 9 and Campylobacter jejuni, particularly in immunocompromised patients.

Clinical manifestations can include tenderness and malaise with the addition of chills and/or fever. There can be induration and pitting edema as a result of the rapid spread of the infection. Lymphangitis may also appear in the vicinity of the erythema. Chronic attacks of cellulitis may lead to elephantiasis. 10

Dissecting cellulitis, also known by the more cumbersome term perifollicutis capitis abscedens et suffodiens ( Figure 4 ), only partially meets the criteria for cellulitis. While there is induration, erythema, and edema, there are also accompanying pustular openings and subsequent crusting.

Nonbacterial Cellulitis

If the definition of cellulitis denotes bacterial origin, then several diseases are as misnamed as is pyogenic granuloma, which has no overt bacterial origin. These include recurrent preseptal cellulitis, which appears to be a factitial entity not due to bacteria, and breast cellulitis, also called isolated erythema of the breast, that does not have a bacterial cause. 11 Cervical carcinoma may metastasize to the skin, producing red induration, at which point it is termed cellulitis-like cutaneous metastasis. To add to the confusion, eosinophilic cellulitis, also called Wells syndrome, has a cellulitic component without bacteria being involved 12 ; sometimes a viral etiology is even suggested.

Unnecessary Confusion

A clinical presentation of erythema and induration may be found in both stasis dermatitis, for example, and cellulitis. Because these signs are present, this does not make the cutaneous findings of venous insufficiency an infectious disease. Similarly, oozing and crusting superimposed on dusky, erythematous skin suggest bacterial superinfection, but they do not create the picture of cellulitis ( Figure 5 ).

Conclusions

Cellulitis is a specific sign with recognized etiologies. The word should not have its meaning diluted by extensions of its definition, nor should cellulitis be used inappropriately.

Clinical manifestations can include tenderness and malaise with the addition of chills and/or fever. There can be induration and pitting edema as a result of the rapid spread of the infection. Lymphangitis may also appear in the vicinity of the erythema. Chronic attacks of cellulitis may lead to elephantiasis. 10

Dissecting cellulitis, also known by the more cumbersome term perifollicutis capitis abscedens et suffodiens ( Figure 4 ), only partially meets the criteria for cellulitis. While there is induration, erythema, and edema, there are also accompanying pustular openings and subsequent crusting.

Nonbacterial Cellulitis

If the definition of cellulitis denotes bacterial origin, then several diseases are as misnamed as is pyogenic granuloma, which has no overt bacterial origin. These include recurrent preseptal cellulitis, which appears to be a factitial entity not due to bacteria, and breast cellulitis, also called isolated erythema of the breast, that does not have a bacterial cause. 11 Cervical carcinoma may metastasize to the skin, producing red induration, at which point it is termed cellulitis-like cutaneous metastasis. To add to the confusion, eosinophilic cellulitis, also called Wells syndrome, has a cellulitic component without bacteria being involved 12 ; sometimes a viral etiology is even suggested.

Unnecessary Confusion

A clinical presentation of erythema and induration may be found in both stasis dermatitis, for example, and cellulitis. Because these signs are present, this does not make the cutaneous findings of venous insufficiency an infectious disease. Similarly, oozing and crusting superimposed on dusky, erythematous skin suggest bacterial superinfection, but they do not create the picture of cellulitis ( Figure 5 ).

Conclusions

Cellulitis is a specific sign with recognized etiologies. The word should not have its meaning diluted by extensions of its definition, nor should cellulitis be used inappropriately.

References

1 Leider M, Rosenblum M. A Dictionary of Dermatological Words, Terms and Phrases. New York, NY: McGraw-Hill; 1968.
2 Grosshans EM. The red face: erysipelas. Clin Dermatol. 1993;11:307–313.
3 Lazzarini L, Conti E, Tositti G, et al. Erysipelas and cellulitis: clinical and microbiological spectrum in an Italian tertiary care hospital. J Infect. 2005;51:383–389.
4 Parish LC, Jungkind DL. Systemic antimicrobial therapy for skin and skin structure infections: comparison of fleroxacin and ceftazidime. Am J Med. 1993;94:166S–173S.
5 Witkowski JA, Parish LC. Bacterial skin infections: management of common streptococcal and stapylococcal lesions. Postgrad Med. 1982;72:166–168, 171–173, 176–178 passim.
6 Mathur MN, Patrick WG, Unsworth IP, et al. Cellulitis owing to Aeromonas hydrophilia: treatment with hyperbaric oxygen. Aust N Z J Surg. 1995;65:367–369.
7 Lee SY, Chuang YC, Young CD. Extensive cellulitis with septic shock caused by Vibrio vulnificus infection-a case report with review of literature. Kansenshogaku Zasshi. 1991;65:1484–1487.
8 Bradaric N, Milas I, Luksic B, et al. Erysipelas-like cellulitis with Pasteurella multocida bacteremia after a cat bite. Croat Med J. 2000;41:446–449.
9 Bornstein PF, Ditto AM, Noskin GA. Serratia marcescens cellulitis in a patient on hemodialysis. Am J Nephrol. 1992;12:374–376.
10 Bonnetblanc JM, Bedane C. Erysipelas: recognition and management. Am J Clin Dermatol. 2003;4:157–163.
11 Miller SR, Mondry T, Reed JS, et al. Delayed cellulitis associated with conservative therapy for breast cancer. J Surg Oncol. 1998;67:242–245.
12 Chung CL, Cusack CA. Wells syndrome: an enigmatic and therapeutically challenging disease. J Drugs Dermatol. 2006;5:908–911.

SKINmed: Dermatology for the Clinician. 6;6:261-263 (November/December 2007)

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