Prophylaxis for Leg Cellulitis

Summary and Comment |
May 1, 2013

Prophylaxis for Leg Cellulitis

  1. Mark V. Dahl, MD

Patients with leg cellulitis who received prophylactic penicillin had fewer recurrences than those given placebo, without increases in adverse effects.

  1. Mark V. Dahl, MD

Leg cellulitis is common and often recurrent. Does continuous treatment with phenoxymethylpenicillin 250 mg twice daily prevent recurrence? To answer this question, investigators enrolled 274 subjects with recurrent cellulitis seen at 28 hospitals in the U.K. and Ireland into a 36-month, double-blind, randomized, placebo-controlled trial of this prophylactic low-dose penicillin. Eligible patients had had a recurrent episode of leg cellulitis within 24 weeks of the enrollment date and at least two other episodes of leg cellulitis within the previous 3 years. The primary outcome was time from randomization to first recurrence.

Median time to first confirmed recurrence was 626 days in the phenoxymethylpenicillin group versus 532 days in the placebo group. Despite prophylaxis, cellulitis recurred in 30 of 136 active-treatment recipients (22%) compared with 51 of 138 placebo recipients (37%) — a hazard ratio of 0.55 (95% confidence interval, 0.35 to 0.86; P=0.01) with treatment, meaning five patients with recurrent cellulitis would need to be treated to prevent one recurrence. During a follow-up period without intervention, the rate of leg cellulitis was 27% in both groups (P=0.88). Univariable and multivariable analysis identified some factors associated with poor response to treatment — high body-mass index, having had three or more previous cellulitis episodes, and leg edema.


Infectious cellulitis causes pain, disability, and, often, expensive treatments and hospitalization. This very well-designed and well-executed study shows that low-dose oral phenoxymethylpenicillin can decrease the incidence of recurrent cellulitis, especially during active treatment. Because the most common infecting bacteria are group A streptococci, drug resistance is unlikely. These findings mirror results of several smaller studies.

Diagnosis of cellulitis depends on clinical criteria. In this study, the diagnosis was made mostly by dermatologists likely to be familiar with such look-alike skin diseases as stasis dermatitis and dermatoliposclerosis. Tinea pedis or toe-web maceration was present in about one third of patients in both groups. Because cracked interdigital skin may be an entry point for bacteria, in my opinion, recurrently infected or macerated toe webs should be treated with appropriate topical prophylactic therapy as an additional preventive step. Higher doses of prophylactic penicillin might be necessary in overweight individuals.


Reader Comments (4)

Arnold Kleinmd Physician, Dermatology, office

An increasing cause of cellulitis in my practice is methicillin-resistant Staphylococcus aureus (MRSA), which can generate prolonged and debilitating infections. These bacteria are resistant to all currently available penicillins and cephalosporins. If MRSA infection is a possibility, the antibiotics of choice in the outdoors are trimethoprim-sulfamethoxazole, doxycycline, or clindamycin. (Other drugs that are often prescribed by a physician once the diagnosis is confirmed include linezolid. ) High-risk persons for MRSA infection include contacts of a person with a MRSA infection, children, male homosexuals, soldiers, prisoners, athletes (especially in contact sports), Native Americans, Pacific Islanders. A retrospective cohort study was conducted in a teaching ambulatory-care clinic of a tertiary medical center in Honolulu.Of 137 cases with cellulitis diagnosed from January 2005 to December 2007, MRSA was recovered from 85 (62%) of patients who presented with either abscesses or skin ulcers. The recovery of MRSA was significantly associated with obesity (p=0.01), presence of abscesses (p=0.01), and lesions involving the head and neck (p=0.04). While the manufacturer advises against the use of linezolid for community-acquired pneumonia or uncomplicated skin and soft tissue infections caused by MRSA it frequently ends up my choice.

Norman M. Canter M.D.

The most common portal of entry...interdigital creases between the toes. The most common abnormality is athlete's foot or dematophytosis. The daily bathing of the feet, antifungal liquid spray, wearing of absorbent socks of cotton, changed daily, the use of shoes (leather) that can "breathe" and air-conditioning in very humid and warm weather will minimize episodes of cellulitis. Strep, sensitive to penicilin is the usual organism. Elevation and inactivity is required during acute episodes. For those who are unable to wear elastic stocking on a chronic basis, some elevation of the foot of the bed can help, periodic elevation during the day, and avoidance of belts with a preference for suspenders will lessen venous back pressure. Veins should be studies and diseased superficial incompetent veins selectively removed where indicated. Cellulitis, acute, of the lower leg is known also as St. Anthony's Rose.

Competing interests: None declared

Silvio D. Pitlik, MD

Leg edema is a common and important risk factor for recurrency of celluliis. Treatment of edema by elastic bandages and other non- pharmacological meassures could have prevented even more episodes of cellulitis than penicillin. Furthermore, the authors completely ignore the deleterious effect on the gut microbiota caused by prolonged administration of an antibiotic.

Competing interests: None declared

Ranya Lotfi

In those patients receiving prophylaxis, what was the treatment regimen used when they got the cellulitis episodes?

Competing interests: None declared

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