AllergyCases: Procedure Guide: Punch Biopsy of the Skin

Author: V. Dimov, M.D., Allergist/Immunologist and Assistant Professor at University of Chicago
Reviewer: S. Randhawa, M.D., Allergist/Immunologist and Assistant Professor at LSU (Shreveport) Department of Allergy and Immunology

1. Get to know the equipment in the standard skin biopsy kit.

2. Explain the procedure to the patient and obtain a written informed consent. Explain the risks, benefits and alternatives (RBA). Always tell the patient that a small scar will remain at the site of the biopsy. Explain what is going on while performing the procedure, this will alleviate both the patient's anxiety and yours.

3. Get the skin biopsy kit at the bedside. You can briefly explain to the patient what the different parts of kit are used for.

4. Mark the area of the skin biopsy with a pen. Mark a circular area (5 mm) on the edge between healthy and diseased skin. Divide the circle in two. One half will be sent for microscopy, the other half for immunofluorescence.

5. Disinfect the area with Betadine (povidone-iodine (PVPI) in a circular fashion from the center out.

6. Draw lidocaine with a large bore needle. Change the needle to in insulin needle (or 30G) and bend it at 45 degrees. Inject lidocaine below the marked area to produce a wealth with a diameter of 2 cm. Wait 1-2 minutes for the lidocaine to take effect.

7. Take the punch biopsy device and apply pressure while rotating it from side to side. Lift the device and remove the biopsied skin specimen (usually the size of a pencil eraser).

8. Stop the bleeding by applying pressure with a 4x4 gauze.

9. The lines of least skin tension are determined. The wound has an elliptical shape that can be closed with sutures parallel to the lines of least skin tension. Apply 1-2 sutures at the biopsy site.

10. Cut the skin biopsy specimen in half along the marked line. Ensure that each half contains both health and diseases skin (as marked). One half is sent for microscopy, the other half for immunofluorescence. Complete the required paperwork and enclose it with the 2 containers. Transport in bio hazard bags.

11. Inform the patient to return to the clinic in one week to remove the suture(s). The patient should keep the area of the biopsy dry for 48 hours.

Disclaimer

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References

Punch Biopsy of the Skin. AFP, 2002.
The Skin Punch Biopsy. J. M. Blakeman. Can Fam Physician. 1983 May; 29: 971–974.

Patient Information

Punch Biopsy of the Skin. AFP, 2002.
Skin lesion biopsy. U.S. National Library of Medicine, 2008.

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