MOHS Surgery

Mohs Surgery Side Effects: Everything You Need to Know

Updated on May 15, 2023, by Don Mehrabi

Mohs surgery is the most successful skin cancer treatment. According to the American College of Mohs Surgery, it has a 99% cure rate for basal cell cancers and a 95% cure rate for squamous cell and recurrent cancers. It is also generally considered safe as most people recover smoothly without serious complications. However, all surgeries have some degree of risk. Hence, in this article, we will talk about Mohs surgery’s side effects to learn more about it.

Despite the high success rate and low risk of complications, you might experience complications and side effects after undergoing Mohs surgery. This article highlights the side effects and complications of Mohs surgery.

What Is Mohs Surgery?

Mohs surgery, also called Mohs micrographic surgery, is a technique of removing skin cancers that involves cutting away the tumor in layers. During the surgery, the Mohs surgeon removes the visible portion of the tumor and a thin layer of surrounding healthy tissue. They divide the excised tissue into sections and examine each under a microscope to check for cancer cells. If any section has cancer cells, the surgeon removes another layer from the affected area and examines it for cancer cells. 

This process continues until the surgeon removes all the tissues with cancer cells. When the surgeon can’t find cancer cells in the excised tissue, they repair the surgical wound. This procedure minimizes the removal of healthy skin and maximizes the preservation of healthy tissue.

Mohs surgery is the most effective treatment for the two most common types of skin cancer: basal cell carcinomas and squamous cell carcinomas. It has also been used successfully in some cases of melanoma.

what is mohs

What Are the Benefits of Mohs Surgery?

Mohs surgery offers many benefits as a skin cancer treatment option. They include the following:

High Cure Rates

Mohs surgery has a 99% cure rate for basal cell cancers and a 95% cure rate for squamous cell and recurrent cancers. So, patients have a high likelihood of eliminating the cancer cells successfully. Patients are also less likely to need further inventions.

Maximal Tumor Removal and Tissue Preservation

The Mohs surgeon cuts away layer by layer and examines each in real-time. This allows them to accurately determine the extent of the tumor and remove all of it until the remaining tissue has no cancerous cells.

Targeting also ensures they don’t remove any healthy tissues, which is particularly important for tumors in cosmetically sensitive areas like the face.

Minimal Scar Formation

Mohs surgery removes only tissues with cancerous cells, so it minimizes the size of the scar by preserving as much healthy tissue as possible.

Immediate Reconstruction

The surgeon can perform a skin graft on the same day if the patient wants. Immediate reconstruction reduces wound closure time and results in better cosmetic results.

Suitable for Complex Cases

Mohs surgery is accurate and effective at treating all sizes of skin cancers, including large, recurrent, and aggressive cancers in challenging areas. This makes it an excellent treatment option for complex cases.

Reduced Risk of Recurrence

The meticulous technique of examining the tissue removed in real-time, mapping, and tracking ensures all cancerous cells are removed. This technique reduces the risk of leaving behind any remaining cancer cells, thereby reducing the chances of recurrence. You won’t need any repeat surgeries or additional interventions.

benefits of mohs

What Are the Side Effects of Mohs Surgery?

Most people who undergo Mohs surgery have different experiences after the surgery. Some experience complications and side effects, while others don’t. Some Mohs surgery side effects and complications occur days or weeks after the procedure, while others occur immediately. Complications and side effects also vary in severity depending on the size and location of the wound.

Common Mohs surgery side effects include the following:

1. Bleeding

Bleeding is a sign that your post-surgical wound has opened while it has not yet fully healed. The first thing to do to manage the condition is to apply pressure on the site with clean gauze. Seek medical attention immediately and inform your Mohs surgeon.

2. Pain and Swelling

After the local anesthesia wears off, you will experience pain and discomfort around the surgical site. Most surgical procedures, including Mohs surgery, leave patients with mild to excessive swelling. The swelling goes away a few days or weeks after the surgery. 

3. Scarring

Scarring is always a possibility in any surgical procedure. To minimize your scarring risk, entrust the procedure only to a board-certified Mohs surgeon and follow their pre- and post-treatment instructions meticulously. If scarring still occurs, reconstructive surgery and lasers can help improve the lesion.

side effect of mohs

4. Partial or Full Necrosis

Necrosis occurs when the tissue at the wound site dies. Partial necrosis is the death of some parts of the tissue, while full necrosis is complete tissue death. Necrosis can be caused by excessive tissue trauma, infection, compromised blood supply to the site if a skin graft is present, etc. Too tight sutures can also stifle cells. Symptoms of necrosis include severe pain and mucous or bloody discharge from the post-surgical site, which should prompt immediate medical attention.

5. Infection

Any surgical procedure is an infection risk if not performed according to the strictest surgical standards. Infection may also be due to poor wound care. A board-certified Mohs surgeon performs this procedure in a sterile environment with sterile equipment, so the risk of infection is minimal. Still, if you develop fever or pus on the postop wound, seek medical help right away and inform your Mohs provider.

6. Nerve Damage

During tumor and tissue removal, the surgeon can sever superficial nerves. The area may become numb, tingly, or feel different. Most cases of superficial nerve damage resolve over time as superficial nerves regenerate and restore sensation. Consult a medical professional if these symptoms persist after the postop wound is fully healed.

7. Allergic Reactions

Some patients may break out into a skin rash after Mohs surgery. The rash can result from an allergic reaction to the surgical tape covering the wound. Though rare, some people can have allergic reactions to Lidocaine, the standard local anesthetic used for Mohs surgery. It can lead to redness, irritation, or swelling at the injection site.

8. Recurrence

Despite its high cure rate, the cancer can recur after Mohs surgery. You should get skin examinations regularly to catch it at its earliest stages if it recurs.

9. Delayed Healing

The surgical site can take longer to heal due to factors like medical conditions and poor blood circulation as you heal. It increases the risk of infection and contributes to more noticeable scarring. If the surgery was performed in a sensitive area like near joints or mouth, delayed healing affects its functionality longer. It can also affect an individual’s body image and self-esteem.

However, it is important to note that these side effects of Mohs surgery are infrequent. According to a study, out of 20,821 Mohs surgeries, only 149 had adverse events (0.72%), and only 4 had serious events (0.02%). The most common adverse events in order are:

  • Infections
  • Dehiscence
  • Partial or full necrosis
  • Bleeding and hematoma

mohs side effects

What Should You Do When You Experience the Mohs Surgery Side Effects?

If you experience the side effects of Mohs surgery, you should take the appropriate steps to manage and address them. Here are some tips and best practices for managing them.

  • Take medications as prescribed.
  • Stay hydrated.
  • Follow the surgeon’s postoperative care instructions.
  • Keep the surgical site clean and dry.
  • Apply ice packs to the affected area to reduce swelling and pain.
  • Avoid strenuous activity or heavy lifting for a few days after the procedure.
  • Keep the wound clean and dry to prevent infection.
  • Protect the site from direct sunlight.
  • Eat a balanced diet.
  • Rest as much as possible to allow your body to heal.
  • Don’t miss follow-up appointments.

Proper side-effect and complication management promotes healing, reduces discomfort, and minimizes complications.

When Should You Seek Medical Advice After Mohs Surgery?

You should seek medical advice after Mohs surgery if you notice the following:

  • Signs of infection like redness, swelling, warmth, pain, or pus-like drainage from the site.
  • Bleeding from the wound that does not stop or starts up again after stopping.
  • A feeling of tightness or pressure around the wound.
  • Signs of an allergic reaction include rash, itching, or difficulty breathing.
  • Fever or other signs of illness.
  • Worsening pain that pain medications can’t relieve.
  • Delayed healing
  • Worsening swelling or bruising

You should also seek medical advice if you have any questions, concerns, or uncertainties regarding your Mohs surgery recovery. They can guide and reassure you.

mohs medical advice

Where to Get Mohs Surgery in LA

Mohs surgery is a technique for removing skin cancer that involves cutting away the tumor in layers. It is highly effective and offers benefits like minimal scar formation, reduced risk of recurrence, and maximal tissue preservation. It is also suitable for complex skin cancer cases.

However, Mohs surgery side effects may exist. It can lead to complications and side effects like bleeding, scarring, pain, necrosis, nerve damage, and delayed healing. If you experience these side effects, you should take steps to manage them. But if they show signs of infection, excessive bleeding, worsening pain or swelling, and the other signs we have discussed, you should seek medical advice.

If you are in Los Angeles, remember that BHSkin Dermatology has some of the best Mohs surgeons in California. Visit us at our Glendale or Encino clinic, or use our virtual portal for your initial consultation to determine if surgery is the best treatment option. Book your appointment today!


Author: Don Mehrabi

Don Mehrabi, MD, FAAD, is LA’s leading board-certified dermatologist who treats patients, builds the BHSkin clinics, and raises three kids. This blog builds on medical studies combined with Dr. Mehrabi's first-hand experiences from practicing in Encino-Tarzana, Glendale, and online

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