Merck Manual

Please confirm that you are a health care professional

honeypot link

How To Do Local Wound Infiltration


Richard Pescatore

, DO, Delaware Division of Public Health

Reviewed/Revised Oct 2021 | Modified Sep 2022
Topic Resources

Local anesthetic can be injected directly into the exposed subcutaneous tissue of an open skin wound before cleansing, repair, and closure.

Local wound infiltration (infiltration anesthesia) is commonly done and often considered procedurally simpler than nerve blockade (regional anesthesia).


  • Laceration or other surgically treated skin lesion

  • Foreign body removal

  • Incision and drainage


Absolute contraindications

  • History of allergy to the anesthetic agent or delivery vehicle (choose a different anesthetic)

Relative contraindications

  • Large wounds (local infiltration of which may require toxic amounts of anesthetic)*

  • Wounds requiring precise anatomic alignment (eg, vermilion border lip lacerations), for which wound edge distortion caused by infiltration is problematic*


  • Adverse reaction to the anesthetic Local anesthesia for laceration treatment (eg, allergic reaction to the anesthetic [rare] or to methylparaben [a preservative])

  • Toxicity due to anesthetic overdose (eg, seizure, cardiac arrhythmias) or sympathomimetic effects due to epinephrine

  • Intravascular injection of anesthetic/epinephrine

  • Hematoma

  • Spread of infection, by passing the needle through an infected area


  • Nonsterile gloves

  • Barrier precautions as indicated (eg, face mask, safety glasses or face shield, cap and gown)

  • Antiseptic solution (eg, chlorhexidine, povidone-iodine, alcohol)

  • Syringe (eg, 1 to 10 mL) and needle (eg, 25 or 27 gauge) for anesthetic injection

  • Injectable local anesthetic* (eg, 1% lidocaine† with or without epinephrine‡ 1:100,000, 25-gauge needle)

  • Topical anesthetic§ (eg, LET solution: 4% lidocaine, 0.1% epinephrine, 0.5% tetracaine) plus cotton ball or dental pledget; optional and often used for children

  • Tissue forceps (eg, Adson forceps), tissue hook as needed to expose the sides of the wound

  • #11 scalpel blade for tissue undermining and debridement (if needed)

† Maximum dose of local anesthetics: Lidocaine without epinephrine, 5 mg/kg; lidocaine with epinephrine, 7 mg/kg; bupivacaine, 1.5 mg/kg. NOTE: A 1% solution (of any substance) represents 10 mg/mL (1 g/100 mL).

Epinephrine causes vasoconstriction, which enhances hemostasis and prolongs the anesthetic effect. Patients with cardiac disease should receive only limited amounts of epinephrine (maximum 3.5 mL of solution containing 1:100,000 epinephrine); alternatively, use local anesthetic without epinephrine. Consider avoiding epinephrine in the distal extremities of patients with peripheral vascular disease.

§ The maximum dose of LET topical solution is 3 mL. When LET and lidocaine infiltration are used together, the sum of the lidocaine doses must not exceed 5 mg/kg.

Additional Considerations

Relevant Anatomy

  • Intradermal anesthetic injection is painful. Inject subdermally (subcutaneously) to cause less pain during local wound infiltration.


  • Position the patient comfortably, with the wound exposed and well-illuminated.

Step-by-Step Description of Procedure

  • Do a neurovascular examination of structures distal to the wound.

  • Wear gloves and use appropriate barrier precautions.

  • Cleanse the skin from the wound edges outward, making several outwardly expanding circles with antiseptic solution. Do not introduce a cleansing agent directly into the wound because many are toxic to tissues and may interfere with wound healing.

Topical anesthesia (optional, for children and anxious adults)

  • Soak a cotton dental pledget (or cotton ball) the length of the wound in several mL of the topical solution and place it within the wound for 30 minutes.

  • If anesthesia is incomplete, give supplementary local infiltration anesthesia through the partially anesthetized wound edges (usually resulting in only minimal pain).

Local infiltration anesthesia

  • Hold the local anesthetic syringe at a shallow angle to the skin.

  • Insert the needle directly into the exposed subdermal layer of the wound edge (ie, do not insert the needle percutaneously) and advance the needle to the hub.

  • Aspirate to exclude intravascular placement and then slowly inject the anesthetic while withdrawing the needle.

  • Redirect the already injected needle into unanesthetized skin to maximize the area anesthetized with a single needlestick. Continue to anesthetize, covering the entire wound circumference.

    For grossly contaminated or infected wounds, consider injecting instead percutaneously through the intact, uninfected (or otherwise disinfected) skin around the wound (field block).

  • Allow several minutes for the anesthetic to take effect. You may gently massage the overlying skin with your fingertip to facilitate spread of the anesthetic in the tissues.

How To Anesthetize Wounds Using Local Infiltration

Tips and Tricks

  • Inject directly into clean wound edges, rather than through adjacent intact skin. It is less painful and does not increase the risk of wound infection.

  • Position the needle along the long axis of the wound making only a single injection (or minimum number of injections) necessary to anesthetize each side of the wound.

  • Consider anesthetizing wounds before cleansing and irrigating, because these procedures can be quite painful.

  • Consider using topical anesthetics particularly for wounds of the face and scalp and those closed by topical skin adhesives.

  • Minimize the pain of injection Local anesthesia for laceration treatment by injecting slowly (eg, 30 to 60 seconds), warming the anesthetic solution to body temperature, and buffering the anesthetic.

Drugs Mentioned In This Article

Drug Name Select Trade
Adrenaclick, Adrenalin, Auvi-Q, Epifrin, EpiPen, Epipen Jr , Primatene Mist, SYMJEPI, Twinject
Betasept, Chlorostat, Hibiclens, Oro Clense , Peridex, Periogard, PerioRx , Perisol
Betadine, Betadine Prep, First Aid, GRx Dyne, GRx Dyne Scrub, Povidex , Povidex Peri
7T Lido, Akten , ALOCANE, ANASTIA, AneCream, Anestacon, Aspercreme with Lidocaine, Astero , BenGay, Blue Tube, Blue-Emu, CidalEaze, DermacinRx Lidogel, DermacinRx Lidorex, DERMALID, Ela-Max, GEN7T, Glydo, Gold Bond, LidaMantle, Lidocan, Lidocare, Lidoderm, LidoDose, LidoDose Pediatric, Lidofore, LidoHeal-90, LIDO-K , Lidomar , Lidomark, LidoReal-30, LidoRx, Lidosense 4 , Lidosense 5, Lidosol, Lidosol-50, LIDO-SORB, Lidotral, Lidovix L, LIDOZION, Lidozo, LMX 4, LMX 4 with Tegaderm, LMX 5, LTA, Lydexa, Moxicaine, Numbonex, ReadySharp Lidocaine, RectaSmoothe, RectiCare, Salonpas Lidocaine, Senatec, Solarcaine, SUN BURNT PLUS, Tranzarel, Xyliderm, Xylocaine, Xylocaine Dental, Xylocaine in Dextrose, Xylocaine MPF, Xylocaine Topical, Xylocaine Topical Jelly, Xylocaine Topical Solution, Xylocaine Viscous, Zilactin-L, Zingo, Zionodi, ZTlido
Marcaine, Marcaine Spinal, POSIMIR, Sensorcaine, Sensorcaine MPF , Xaracoll
NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
quiz link

Test your knowledge

Take a Quiz!