When you notice a rash or a worrisome mole on your skin, which is the largest organ in your body, it’s a good idea to see a dermatologist for an evaluation. Sometimes after examining the area, a dermatologist may recommend a skin biopsy.
Skin biopsies are an important part of verifying the diagnosis. For example, a biopsy is the only way for a doctor to confirm and determine the severity of melanoma – the most dangerous type of skin cancer. A skin biopsy may also be used to confirm that a skin tumor is benign or to diagnose inflammatory skin conditions such as drug-related rash or eczema.
Here are the Quick 5 steps involved:
1. A dermatologist examines your skin
Patients see dermatologists for a variety of reasons, including concern about a specific skin lesion or a worsening of the rash. In addition, patients at risk of developing skin cancer undergo a comprehensive examination of the skin of the body at regular intervals. Sometimes the patient may be referred to a dermatologist by their primary care physician for more specialized expertise. If you have a skin problem, your dermatologist will evaluate it during the office visit, and ask questions about your skin problem and how long you’ve had it.
2. The dermatologist decides whether a skin biopsy is needed
Skin biopsies are most commonly done on an outpatient basis during an appointment with a dermatologist. After examining the rash or lesion felt by the patient or the doctor, the patient is asked questions regarding its history. The dermatologist then decides if a skin biopsy is necessary. If a rash is present, a new but well-developed lesion is selected and, if possible, in a place of minimal cosmetic concern, if possible. After a thorough examination of the skin of the body, a biopsy is taken of the lesions of most concern. Sometimes, a biopsy may be done a week or two later if the skin condition is not considered severe or life-threatening.
3. The doctor gives local anesthesia
The biopsy area is cleaned, usually with alcohol, and then a local anesthetic such as lidocaine is injected to numb the area using a very thin needle. Lidocaine solution often contains epinephrine (to reduce bleeding) and sodium bicarbonate (to reduce the burning sensation). The patient will feel a slight pinch of the needle, and then a brief burning sensation while the anesthetic is injected. Pressure may also be felt when a local anesthetic is injected into a relatively tight area of skin, such as the fingers or toes. If the patient is concerned about the injection, a local anesthetic may be applied 1 to 2 hours prior to the procedure to reduce associated pain.
4. A dermatologist performs the correct type of biopsy
The type of the biopsy a patient needs is determined by the size and the location of the lesion, the depth of the skin problem, and the information sought based on the most likely diagnoses. The experience of a dermatologist is crucial to making this decision. Types of biopsies include:
Razor biopsies are used when a dermatologist suspects that a condition or tumor primarily involves the top layer of skin (the epidermis). The biopsy sample includes the epidermis and sometimes the superficial part of the dermis (the second layer of skin). The blade of the scalpel is slightly bent when performing this procedure.
The dressing is done if the dermatologist thinks the disease or tumor extends into the upper or middle dermis. In this type of the biopsy, the edge of the blade is at a greater angle relative to the surface of the skin. This type of biopsy is most often done on the stump.
A perforated biopsy is a technique that involves a circular blade similar to a cookie cutter. It enters the skin in a gentle rotation. A perforation biopsy is performed when a disease or tumor is thought to involve the deep dermis and/or when suture placement is planned.
An excisional biopsy is done when a disease or tumor is thought to involve the deep dermis and possibly the subcutaneous fat. If a tumor is present, the goal is complete excision. Sutures are placed to close the wound. Sometimes the tumor is too large to be completely removed or a partial biopsy is sufficient (for example, for inflammatory diseases) and a cross-sectional biopsy is performed.
5. Post-operative care is provided after a skin biopsy is taken
After a skin biopsy, you should take good care of the biopsy area at home. To speed healing, keep the biopsy site moist by applying an ointment that prevents scabies and reduces scarring. A small edge of redness usually appears at the edge of a healed wound but widening redness, fever, chills, pus, or severe pain can be signs of an infection, which is uncommon.
Recovery time varies and depends on the size and depth of the biopsy, the anatomical location (the face heals much faster than the ankle), and any underlying medical conditions you may have. Most of the biopsy sites heal within 2 to 3 weeks.