No evidence that routine preoperative hair removal reduces surgical site infection

Traditionally, patients undergoing surgery have hair removed from the site of the incision, as this is thought to reduce the chance of the surgical site becoming infected. Hair can be removed by several different methods which include shaving, clipping the hair and using a cream which dissolves the hair. Existing research studies are too small and methodologically flawed to allow us to draw strong conclusions; on the basis of existing evidence it is not clear whether hair removal pre-operatively affects rates of surgical site infections. However if hair has to be removed to facilitate surgery or the application of adhesive dressings, clipping rather than shaving appears to result in fewer surgical site infections.

Authors' conclusions: 

Whilst this review found no statistically significant effect on SSI rates of hair removal insufficient numbers of people have been involved in this research to allow confidence in a conclusion. When it is necessary to remove hair, the existing evidence suggests that clippers are associated with fewer SSIs than razors. There was no significant difference in SSI rates between depilatory creams and shaving, or between shaving or clipping the day before surgery or on the day of surgery however studies were small and more research is needed.

Read the full abstract...

Although preparation of people for surgery has traditionally included removal of hair from the incision site, some studies claim that preoperative hair removal is harmful, causes surgical site infections (SSIs), and should be avoided.


To determine if routine pre-operative hair removal (compared with no removal) and the timing or method of hair removal influence rates of SSI..

Search strategy: 

For this second update we searched the Cochrane Wounds Group Specialised Register (searched 12 August 2011); The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 3); Ovid MEDLINE (1950 to August Week 1 2011); Ovid MEDLINE (In-Process & Other Non-Indexed Citations August 11, 2010); Ovid EMBASE (1980 to 2011 Week 31) and EBSCO CINAHL (1982 to 11August 2011). No date or language restrictions were applied.

Selection criteria: 

Randomised controlled trials (RCTs) or quasi randomised trials (QRCTs) that compared:

1) hair removal with no hair removal;
2) different methods of hair removal;
3) hair removal at different times before surgery; and,
4) hair removal in different settings (e.g. ward, anaesthetic room).

Data collection and analysis: 

Three authors independently assessed relevance and quality of each trial. Data were extracted independently by two authors and cross-checked.

Main results: 

We included 14 trials (17 comparisons) in the review; three trials involved multiple comparisons. Six trials, two of which had three comparison arms, (972 participants) compared hair removal (shaving, clipping, or depilatory cream) with no hair removal and found no statistically significant difference in SSI rates however the comparison is underpowered. Three trials (1343 participants) that compared shaving with clipping showed significantly more SSIs associated with shaving (RR 2.09, 95% CI 1.15 to 3.80). Seven trials (1213 participants) found no significant difference in SSI rates when hair removal by shaving was compared with depilatory cream (RR 1.53, 95% CI 0.73 to 3.21), however this comparison is also underpowered. One trial compared two groups that shaved or clipped hair on the day of surgery compared with the day before surgery; there was no statistically significant difference in the number of SSIs between groups however this comparison was also underpowered.

We identified no trials that compared clipping with depilatory cream; or investigated application of depilatory cream at different pre-operative time points, or hair removal in different settings (e.g. ward, anaesthetic room).