I Hate H2O2 (Sometimes)

I was working special event duty this weekend.  A lady presented to the first aid room after a minor fall onto concrete.  She abraded her knees, fairly deeply.  Some of the abrasion could even be described as lacerations.  One of the other medics jumped to it.  He busted open a bottle of 3% hydrogen peroxide, poured it over the lady’s knee wounds, dried it all with a 4x4, and bandaged it all up.

Did he do the right thing for that patient?

I need to put this here so that the next pic isn't the one that constantly shows...

Hydrogen peroxide (H2O2) was used as an antiseptic in this case.  The difference between an antiseptic and an antibiotic is that an antibiotic is usually directed at killing specific bacteria.  An antiseptic is designed to kill or impede most microorganisms – bacteria, fungi, and viruses.  Several antiseptic categories exist, but common ones are alcohols (ethanol), biguanides (chlorhexidine), bisphenols (triclosan), chlorine compounds, iodine compounds, and hydrogen peroxide.  One of the most common antiseptic soaps uses triclosan.  When you swipe an alcohol prep or iodine prep on an arm, you’re using the alcohol as an antiseptic.

Those antiseptics are used externally, though.  Most aren’t designed to be poured into an open wound.  What if an antiseptic kills bacteria, but it also kills human skin cells?  Are there studies that can help us?

In lab conditions, hydrogen peroxide appears to work to kill bacteria.  It works best on Gram-positive bacteria, but when catalase is present (like in living tissue), hydrogen peroxide becomes less effective.(1, 2)  Some studies did not find that hydrogen peroxide messes with wound healing.  For example, Gruber’s group (3) found that peroxide lengthened the healing time of wounds.  This is probably because bullae formed in the wounds, suggesting that hydrogen peroxide should be avoided with new epithelium.  Lineaweaver, et al.,(4) found that wound healing was not inhibited in rats, but this study also found that microorganism load didn’t change a whole lot, either.  Two other studies did not show that hydrogen peroxide was effective as an antiseptic.(5, 6)  One final study on fetal tissue indicates that hydrogen peroxide may increase scarring (7).

So, in short, hydrogen peroxide does not appear to work well as an antiseptic.  This makes sense when you think about it – its not like surgeons pour 3% hydrogen peroxide over incisions, right?  Ever seen an ED physician pour a bottle of peroxide into a laceration before s/he sutures it up?  Nope.  They use clean water irrigation to clean wounds.

"Uh, yeah.  I'm going to need about 15 gallons of hydrogen peroxide, STAT!"
Shotgun wound by DiverDave (Own work) [CC BY-SA 3.0], via Wikimedia Commons

In addition, there seems to be some questions as to whether H2O2 affects wound healing or not.  It appears to be cytotoxic.  So if there is questionable efficacy, plus controversy regarding healing rates, why use it?

Use soap and water.  Copious irrigation with clear water.

For me, hydrogen peroxide is really good for one thing – loosening dried blood, especially on equipment and white shirts.  There are calls after which I pour a bottle of peroxide all over the pram.  The bubbles show where the blood is, plus loosens it up so I don’t have to scrub it off as extensively.  It seems to really help in tight little seams and other hard to reach places.  I also use it to loosen up blood stains on a white shirt.  I’ve not had a shirt ruined since starting to dab with peroxide.

1. Brown CD, Zitelli JA. A review of topical agents for wounds and methods of wounding. J Dermatol Surg Oncol 1993;19:732-7.

2. McDonnell G, Russell AD. Antiseptics and disinfectants: Activity, action and resistance. Clinical Microbiology Reviews 1999;12(1):147-79.

3. Gruber RP, Vistnes L, Pardoe R. The effect of commonly used antiseptics on wound healing. Plast Reconstr Surg 1975;55(4):472-6.

4. Lineaweaver W, Howard R, Soucy D, et al. Topical antimicrobial toxicity. Arch Surg 1985;120(3):267-70.

5. Leyden JJ, Bartelt NM. Comparison of topical antibiotic ointments, a wound protectant and antiseptics in the treatment of human blister wounds contaminated with Staphylococcus aureus. J Fam Pract 1987;24(6):601-4.

6. Lau WY, Wong SH. Randomised, prospective trial of topical hydrogen peroxide in appendectomy wound infection. Am J Surg 1981;142:393-7.

7. Wilgus TA, Bergdall VK, Dipietro LA, Oberyszyn TM. Hydrogen peroxide disrupts scarless fetal wound repair. Wound Repair Regen  2005;13(5): 513–9.