LAUSR

We present a novel technique for performing skin biopsies that only requires a punch biopsy and gauze. We have called the technique pinch biopsy due to the typical movement performed for specimen extraction, as shown in Fig. 1. First, the punch is introduced deep into the hypodermis (Fig. 1A) and, using the thumb and forefinger in a pinching movement, the distal portion of the cylinder is pulled vertically and fully released without causing damage to the sample (Fig. 1B and C). This method can easily be performed using a 5 mm punch on the skin of the trunk, as well as upper and lower limbs. In these locations, the skin cylinder is often partly detached from the hypodermis when pulling the punch and can be safely extracted with a mild traction. A piece of gauze is recommended to prevent the sample from sliding away covered in blood (Fig. 1D) and introduce the sample to the specimen cup. Pinch biopsies can be performed onmost inflammatory diseases except for sclerosing diseases, such as morphea, scleroderma, or panniculitis. In these conditions, skin cylinders tend to sink in rather than readily pop out and it is thus more difficult to collect the skin sample. We do not recommend performing pinch biopsies on sensitive areas, such as the nose, forehead, and scalp, where finger extraction might be more difficult than on other locations. In every other setting, we consider this technique to be advantageous.