Which Came First-the Cellulitis or the Cyst?

My patient is a 70-year-old man who has had several episodesof cellulitis in his right thigh; he does not have diabetes.After the third episode, a 1-cm subcutaneous mass was excisedabove the area of recurrent cellulitis. Histopathologicexamination of the specimen revealed that the mass was afollicular cyst. Could the punctum of the cyst have given skinbacteria entry to the subcutaneous tissues?---- Calvin Kellerman, MD
Merion, Pa
Although the cystic lesion was in close proximityto an area of cellulitis, it is not likely thatthis benign tumor led to the infection. Unlessthe cyst itself had demonstrated signs of inflammation(erythema, heat, tenderness, orspontaneous pain), it probably was not infected. The oppositescenario could be true, however. A cyst might haveformed in response to the infection, as the body attemptedto "wall off" the area of recurrent inflammation.Persons with diabetes are particularly susceptible tolower extremity cellulitis. Possible causes to search for--both in patients with diabetes and in those without--areonychomycosis and tinea pedis. These infections can leadto small (or large) fissures on the pedal surface or in theinterdigital web spaces. Pathogenic bacteria then enterthrough these seemingly minor abnormalities, ascend,and cause cellulitis anywhere from the ankle to the thigh.In fact, aside from traumatic implantation of bacteria orpreexisting open ulcerations, the most common identifiableunderlying cause of lower extremity cellulitis is dermatophyticfungal infection of the foot.¹---- Ted Rosen, MD
Professor of Dermatology
Baylor College of Medicine
Houston

References:

REFERENCE:
1.

Semel JD, Goldin H. Association of athlete’s foot with cellulitis of the lowerextremities: diagnostic value of bacterial cultures of ipsilateral interdigital spacesamples.

Clin Infect Dis.

1996;23:1162-1164.