{"id":1334,"date":"2017-07-10T10:47:39","date_gmt":"2017-07-10T10:47:39","guid":{"rendered":"http:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/?p=1334"},"modified":"2017-09-27T14:08:53","modified_gmt":"2017-09-27T14:08:53","slug":"primary-care-corner-with-geoffrey-modest-antibiotics-for-skin-abscesses","status":"publish","type":"post","link":"http:\/\/stg-blogs.bmj.com\/bmjebmspotlight\/2017\/07\/10\/primary-care-corner-with-geoffrey-modest-antibiotics-for-skin-abscesses\/","title":{"rendered":"Primary Care Corner with Geoffrey Modest: antibiotics for skin abscesses?"},"content":{"rendered":"

by Dr Geoffrey Modest<\/strong><\/p>\n

A\u00a0recent article found\u00a0that either clindamycin or trimethoprim\/sulfamethoxazole (TMP\/SMX) are superior to placebo for uncomplicated skin abscesses (see Daum\u00a0RS. N\u00a0Engl\u00a0J Med 2017;376:2545-55 ).<\/p>\n

Details:<\/strong><\/p>\n

— multicenter, prospective, double-blind trial of 786 outpatient adults and children who had a skin abscess <5 cm in diameter (or <3\u00a0cm if 6-11\u00a0months old, <4 cm if 1-8 yo), and two\u00a0of: erythema, swelling\/induration, local warmth, purulent drainage, tenderness.<\/p>\n

—\u00a0patients\u00a0randomized to clindamycin 150 mg TID vs\u00a0TMP\/SMX 80\/400 mg BID vs placebo, for 10 days<\/p>\n

— 57% male, mean age 25.5 (64%\u00a0> 18yo\/13% 9-17yo\/21%\u00a01-18yo\/2% <1yo),\u00a0\u00a062% African-American\/31% white, temperature 37\u00b0C, area of wound 4 cm\u00b2, surrounding erythema 27 cm\u00b2<\/p>\n

— all had incision and drainage of their abscess<\/p>\n

—\u00a0Exclusion criteria: infection in a body site requiring specialized management (perirectal, genital, hand\u00a0infection), human or animal bites, oral temperature higher than 38.5\u00b0C (38.0\u00b0C in children 6-11 months of age), systemic inflammatory response syndrome, immunosuppressive therapy, immunocompromising conditions (e.g. diabetes, renal failure), BMI >40<\/p>\n

Results:<\/strong><\/p>\n

—\u00a0S. aureus was isolated from 527 (67%); MRSA was isolated from 388 (49%)<\/p>\n

— intention-to-treat analysis 10 days after therapy: cure rate in\u00a0clindamycin group was 83%, TMP\/SMX group 82% (no statistical difference), but in the placebo group was 69%, significantly lower (p<0.001)<\/p>\n

—\u00a0For those who could be evaluated (those that completed the required study visits): 93% of clindamycin group, 93% of TMP\/SMX group, and 81% of placebo were cured.<\/p>\n

— children did slightly better than adults overall, especially in the clindamycin group<\/p>\n

— For those without S. aureus, 90.5% on\u00a0clindamycin, 90.8% on TMP\/SMX , and 90.8% on placebo were cured\u00a0(i.e. no benefit in non-S. aureus infections by antibiotics)<\/p>\n

— for those with S. aureus (similar numbers for MRSA and MSSA), around 95% on clindamycin, 92% on\u00a0TMP\/SMX , and 70% on placebo were cured<\/p>\n

— treatment failure was mostly because of\u00a0a lesion at a different body site, or use of a rescue medication (done\u00a0largely in the placebo group), but rarely due to worsening of the original lesion.<\/p>\n

— at the one month follow-up visit:<\/p>\n

–79% of the clindamycin group, 73% on\u00a0TMP\/SMX , and 63% on placebo\u00a0remained cured.<\/p>\n

–new infections at one month were less common in the clindamycin group (7%), than in the\u00a0TMP\/SMX group (14%), p=0.03, or the placebo group (13%), p=0.06<\/p>\n

— adverse events were more common with clindamycin (22%) than with TMP\/SMX (11%) or placebo (13%). All adverse events were\u00a0without sequelae. One participant on\u00a0TMP\/SMX had a hypersensitivity reaction\u00a0(fever, rash, thrombocytopenia, and hepatitis).\u00a0Most common adverse events were diarrhea (16% clindamycin, 5% TMP\/SMX, 7% placebo) and nausea (2%, 4%, 2%). No C difficile infections<\/p>\n

Commentary:<\/strong><\/p>\n

—\u00a0Skin abscesses are quite common, affecting 4% of people in the United States annually. Often these are treated as outpatients with\u00a0clindamycin or TMP\/SMX,\u00a0 given the large percent of community\u00a0MRSA<\/p>\n

—\u00a0In this study TMP\/SMX was effective at a lower dose than often prescribed, though a 10-day course was given (vs 7 days). It is possible that the cure rates might have been higher with higher doses of\u00a0TMP\/SMX<\/p>\n

—\u00a013\u00a0\u00a0patients had resistance to clindamycin and did not fare as well (54% cure vs 85% in clindamycin-susceptible infections). There were no cases of\u00a0TMP\/SMX\u00a0resistance<\/p>\n

—\u00a0this study suggests that antibiotics help, though held-wisdom previously was that there was not much\u00a0additional benefit after incision and drainage alone.<\/p>\n

—\u00a0there were minimal severe adverse reactions. Prior studies have found about 5% on TMP\/SMX have severe reactions (and 1 person did above), and these can be fatal.<\/p>\n

—\u00a0for clindamycin, there was a meta-analysis (see Brown KA. Antimicrobial Agents and Chemotherapy 2013; 57: 2326) that\u00a0found that, as compared to no antibiotic exposure, the Odds Ratio of C\u00a0difficile infection\u00a0for clindamycin was 16.80, fluoroquinolones 5.50, cephalosporins 5.68, macrolides 2.65, TMP\/SMX\u00a01.81<\/p>\n

—\u00a0it was mentioned in the supplementary materials of the current study\u00a0that 33 in the placebo group (13%) used “rescue meds”, whereas 12 in clindamycin (5%)\u00a0and 15 in TMP\/SMX\u00a0(6%)\u200b\u00a0did. There is no comment on\u00a0what meds were used or what the outcomes were for those who\u00a0continued with their assigned meds\/placebo and did not require rescue meds<\/p>\n

so:<\/p>\n

–it seems quite likely from this study\u00a0that antibiotics help,\u00a0as also noted in a\u00a0prior blog<\/a>\u00a0, a study comparing TMP\/SMX at 4-fold higher doses (320\/1600 mg bid) finding benefit from the antibiotic but noting that >80%\u00a0responded just to I&D.\u00a0\u00a0And, 80+% of people\u00a0seem to get better without antibiotics<\/strong>\u00a0(in several other\u00a0studies), and even in this study,\u00a081% of those completing the study\u00a0were cured. (70% of those\u00a0with\u00a0documented S aureus infections).<\/p>\n

—\u00a0there are really bad\/occasionally lethal\u00a0short-term\u00a0potential adverse events from these antibiotics, especially severe systemic reactions to\u00a0TMP\/SMX and severe C difficile infections with clindamycin<\/p>\n

–and there are potential long-term bad effects on the microbiome. As an example, this blog<\/a> reviews a large prospective observational study finding antibiotic usage was associated with later development of colonic adenomas, including high-risk ones<\/p>\n

–it was also notable\u00a0in this study that there were not many cases of the abscess area getting worse in the placebo group with “treatment failure”<\/p>\n

–so, in lower risk patients (nondiabetics, immunocompromise, etc), it might be reasonable just to watch the patient, holding the antibiotics but prescribing them if they were not getting better in a few days. I would be inclined to use antibiotics even in this lower-risk group if there were uncertainty about being able to have close followup (returning to clinic or phone followup), to assess the progress.<\/p>\n","protected":false},"excerpt":{"rendered":"

antibiotics for skin abscesses? […]<\/p>\n

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