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Clinical Conundrum: Foreign Body - Part 1

Vicky Pittman, PA and Matthieu DeClerck, MD

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How do you decide if you should go after a retained foreign body in the urgent care setting?  Dr. Matthieu DeClerk and UC/EM physician assistant Vicky Pittman discuss an approach to cutaneous foreign bodies, including removal tips and post-removal care.



  • Wound foreign bodies (FB) create an inflammatory response that impairs healing.  This can lead to granuloma formation or infection.

  • Organic materials are more likely to cause an inflammatory reaction than inert materials.

  • Remove FBs that are superficial, organic (wood, thorn), cause cosmetic or functional issues, cause neurovascular issues, and are symptomatic. 

  • Soft tissue x-rays can detect many FBs that are radiopaque (stones, glass, and metal). They do not perform as well at picking up radiolucent FBs (wood, thorns, plastic).


Case:  A middle-aged male presented with a foreign body (FB) sensation at the base of his left thumb just proximal to the MCP joint. He had had pain in that area for a couple of days and could feel something under the skin, but he had no recollection of injury, trauma, or foreign body exposure. On exam, there was no puncture wound and no evidence of infection. However, there was a palpable 1 cm linear mass right in the area of his discomfort. An x-ray showed no radiodense FB. 


  • History and exam are critical when evaluating patients with possible retained FBs.

    • Inquire about the patient’s occupation (ie. carpenter, seamstress), hobbies (ie. gardener), and social history (ie. IVDA).

    • Another clue for a possible FB is a wound that won’t heal or is currently infected. FBs create an inflammatory response that impairs normal wound healing. 

    • If the puncture happened a few days prior, there may no longer be a visible puncture wound.

    • On exam, look for redness, swelling, point tenderness, or neurovascular injury.

  • When should we think about removing a FB? It depends on 3 factors:

    • Type of foreign body

      • High risk:  organic materials (wood slivers, thorns/spines)

        • More likely to cause an inflammatory response. 

        • Also high risk:  FBs that cause systemic symptoms (ie. sea urchin spines).

      • Low risk:  inert material (glass, metal) 

        • Less likely to cause an inflammatory or infectious reaction.

        • Some of these can be left in place.

    • Depth of the object

      • If the FB is superficial and clearly visible, removal should be attempted.

      • Removal of deeper objects carries a greater risk to surrounding structures. Consider the vessels, nerves, tendons, joints, etc. in the vicinity.

    • Risk vs. benefit of removal

      • Risk:  damage to surrounding structures, infection, granuloma formation

        • High risk areas: hands and feet

      • Benefit:  cosmetic outcomes, functional impairment, ↓ chance of infection, pain control

    • Bottom line: 

      • FBs should be removed if they are superficial, organic (wood, thorn), causing cosmetic or functional issues, causing neurovascular issues, and symptomatic. 

      • FBs do not be removed if they are small, inert (eg, glass, metal bullet), deep, and asymptomatic. 

      • Defer removal to a specialist if:   Failed attempts, FBs in the hand or foot that require extensive/deep exploration, FBs that are too deep or not easily accessible, and any FB where you are uncomfortable/unfamiliar with the surrounding anatomical structures. 

  • Imaging may be necessary to determine the presence, depth, and location of a suspected FB that is not visible.

    • Plain x-ray

      • Under-penetrated x-rays are a good initial choice (detects 80-90% of FBs).

      • Radiographic visibility depends on the radiopacity of the object and its size.

        • Radiopaque FBs = stone, gravel, glass, metal

        • Radiolucent FBs = wood, thorns, plastic

        • Glass that is <2mm may not be visible.

        • Wood is missed on plain films 15% of the time.

      • If the x-ray is negative but you’re still suspicious for FB (especially if you know it’s radiolucent), consider additional imaging.

    • Ultrasound (if available)

      • Can look for radiolucent FBs, diagnose complications of FBs (ie. abscesses), and identify surrounding structures (ie. vessels, tendons, nerves).

      • Can facilitate removal.

    • Others: CT, MRI, fluoroscopy (typically beyond the scope of the UC)

  • Procedure:  FB removal tips

    • Explore every open wound for a FB.

    • Set yourself up for success with good lighting, magnification, and hemostasis.

    • Have the right tools (splinter forceps, 18 gauge needle, #11 blade scalpel, curved hemostat).

    • You may need to extend the incision with a #11 blade to better visualize/grasp the FB. You can also bluntly dissect to the FB using a curved hemostat.

    • Know where you’re going and what are the underlying structures/vessels/nerves.

    • Set a time limit or # of tries. 

      • If it takes more than 15-30 minutes, refer.

      • Being overly aggressive can cause more trauma to the soft tissues.

      • Having a plan for referral takes the pressure off.

    • A punch biopsy or elliptical incision can be used to remove and/or locate more superficial FBs.

  • Post-removal wound care

    • Irrigate the wound.

    • Delayed closure is preferred, but primary closure is reasonable for clean wounds in highly vascularized areas, especially if cosmesis is a concern.

    • Update tetanus immunization if necessary.

    • Prophylactic antibiotics for uninfected wounds?

      • No proven benefit.

      • Many will give antibiotics for:

        • Wounds in high risk, poorly vascularized areas (like the extremities).

        • Very contaminated wounds, especially if you are concerned about retained organic material.

        • Patients with comorbidities that place them at higher risk of infection.

        • For most wounds, coverage should be staph/strep (ie. cephalexin x 3-5 days). 

        • Consider the possibility of pseudomonas if the FB was a result of a puncture through the sole of a shoe.

    • Wound recheck in 48 hours with precautions to return immediately for signs of infection (erythema, fever, local tenderness, purulent drainage).



  1. Halaas GW. Management of Foreign Bodies in the Skin. Am Fam Phys. 2007;76:683-688.

  2. Lewis D, et al. My patient is injured: identifying foregin bodies with ultrasound. Ultrasound. 2015;23(3):174-180.

  3. Peterson JJ, et al. Wooden foreign bodies: imaging appearance. AJR Am J Roentgenol. 2002;178(3):557-562.

  4. Baddour LM, Brown AM. Infectious complications of puncture wounds.  In: Post T, ed. UpToDate. Waltham, MA.: UpToDate; 2016.

  5. Lammers R, Mastenbrook J. Soft Tissue Foreign Bodies. In: Tintinalli JE, Ma O, Yealy DM, Meckler GD, Stapczynski J, Cline DM, Thomas SH. eds. Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 9e New York, NY: McGraw-Hill.

  6. Prevaldi C, et al. Management of traumatic wounds in the Emergency Department: position paper from the Academy of Emergency Medicine and Care (AcEMC) and the World Society of Emergency Surgery (WSES). World J Emerg Surg. 2016;11:30.

Derek A., PA-C -

When unable to remove a deep foreign body in the UC setting. Is it recommended to refer to general surgery or dermatology? Thanks.

Mike W., MD -

From Matt DeClerk:
I would opt for General Surgery or Orthopedic Surgery if it is beyond the skin (aka the muscle).

But if it is in the skin and/or can be done under local anesthesia that is something dermatologists are usually comfortable doing. They often will do a bunch biopsy or excisional biopsy to remove foreign bodies that are deeper in the skin or subcutaneous tissue.

If in doubt it's always wise to have an conversation with the specialist to see if they are comfortable going after it.

Hope this is helpful!


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