Open Wound of the Arm

First aid for an arm wound

1. Stop the bleeding: press firmly on the wound with a clean cloth for 10 minutes without lifting. Raise the arm above heart level.
2. For severe bleeding that does not stop with direct pressure, keep pressing hard and call emergency services. Trained responders may use a tourniquet above the wound for life-threatening limb bleeding.
3. Clean the wound: rinse under running tap water for several minutes. Wash the surrounding skin with soap. Remove visible dirt with tweezers cleaned with alcohol. Do not pour hydrogen peroxide or alcohol into the wound.
4. Protect it: apply a thin layer of petroleum jelly and cover with a nonstick dressing. Change daily or when it gets wet or dirty.
5. Ease pain: acetaminophen (paracetamol) or ibuprofen, following the label dose.

Types of open wound on the arm

When an arm wound needs stitches

Have the wound closed by a clinician if it:

• gapes open or the edges do not come together easily
• is deep enough to show yellow fat, muscle or white tendon
• is over a joint such as the elbow, where movement pulls it open
• is longer than about 2 cm (3/4 inch)

Clean wounds are best closed within about 6 to 12 hours. Options include stitches, staples, adhesive strips and skin glue. Heavily contaminated wounds and bites are sometimes left open or closed later to reduce infection risk.

Deep forearm cuts: tendons, nerves and arteries

The inner forearm and wrist contain the tendons that bend the fingers, the median and ulnar nerves, and the radial and ulnar arteries, all close to the surface. After a deep cut, a clinician will check:

• whether each finger bends and straightens fully against resistance
• sensation on each fingertip
• pulses and color in the hand

A cut tendon or nerve needs repair by a hand surgeon, usually within days. Missing these injuries can leave permanent weakness or numbness. See tendon laceration.

Infected wounds and pus on the arm

An infected or pus-filled wound usually shows itself 1 to 4 days after the injury:

• redness spreading out from the wound
• warmth and swelling
• increasing pain or throbbing, rather than improving pain
• yellow or green pus, or a bad smell
• red streaks running up the arm (lymphangitis)
• swollen tender lymph nodes in the armpit
• fever or chills

A small collection of pus may need opening and draining as an abscess. Spreading redness is cellulitis and needs antibiotics. See infection of an open wound. Severe pain out of proportion to the look of the wound, with dusky skin and fever, can signal necrotizing fasciitis and is an emergency.

Infection is more likely with:

• bites, especially cat bites, which puncture deeply
• dirty wounds, crush injuries and puncture wounds
• diabetes, poor circulation, smoking and weakened immunity
• wounds that were not cleaned well

Bites

Bites to the arm and hand become infected often. Cat bites and human bites (including a "fight bite" from punching teeth) carry especially high risk. All bites should be seen by a clinician, who will clean the wound thoroughly, usually prescribe preventive antibiotics, check tetanus status and assess rabies risk. See animal bite.

Tetanus protection

Get a tetanus booster if your last dose was more than 10 years ago for a clean wound, or more than 5 years ago for a dirty wound, puncture or bite. People who never completed the primary series may also need tetanus immune globulin.

How an arm wound heals

1. First days: bleeding stops, the area is a little red and swollen as inflammation clears debris.
2. Days 3 to 14: new tissue fills the wound and skin grows over it.
3. Weeks to months: the scar strengthens and fades.

To help healing:

• keep the wound moist and covered
• avoid soaking it in baths, pools or hot tubs until it has closed
• keep stitches dry for the first 24 to 48 hours, then follow your clinician's instructions
• do not pick scabs
• protect the new scar from sun for a year to reduce darkening

Frequently asked questions

How do I treat an open wound on my arm?

Press firmly for 10 minutes to stop bleeding, rinse well under running water, wash the skin around it with soap, then cover with petroleum jelly and a nonstick dressing. Change the dressing daily. Get deep, gaping, dirty or bitten wounds seen by a clinician.

Why does the open wound on my arm hurt more after a few days?

Pain should ease day by day. Pain that increases after 2 to 4 days, especially with redness, warmth, swelling or pus, suggests infection. See a doctor promptly, as you may need antibiotics or drainage.

What does a pus-filled wound on my arm mean?

Pus means bacteria have infected the wound and white blood cells are fighting them. A small amount may need draining. Pus with spreading redness, red streaks or fever needs antibiotics. Do not squeeze it, which can push infection deeper.

How long does an open wound on the arm take to heal?

Minor cuts and scrapes usually close within 7 to 14 days. Stitched arm wounds have their stitches removed after about 7 to 10 days. Deep wounds, infected wounds and wounds in people with diabetes or poor circulation take longer.

Should I cover an open wound or let it breathe?

Cover it. Wounds kept clean, moist and covered heal faster and scar less than wounds left to dry out and scab. Use a thin layer of petroleum jelly under a nonstick dressing and change it daily.