Tunnels underneath the skin’s surface mean yourwound isn’t healing well. Tissue is being damaged, and without the right care, even more serious complications can occur.

An open wound is an unsettling sight. But what you may not see underneath the wound can be more unsettling.

Continue reading to find out why tunneling wounds form, how they’re treated, and if there’s any way to prevent them.

A tunneling wound is a wound that’s progressed to form passageways underneath the surface of the skin. These tunnels can be short or long, shallow or deep, and can take twists and turns.

Tunneling can occur in stage 3 and stage 4 pressure ulcers.

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Tunneling on edge of wound. Credit Image: Chinnabanchon9Job/Shutterstock

You may have a wound that appears to affect only the surface of the skin, but if you don’t get the right treatment, it can turn into a tunneling wound. Also, tunnels aren’t always visible, so it’s wise to have all wounds checked out.

A doctor will probe the wound to determine if there are tunnels, how long and deep they are, and what direction they’re heading.

Tunneling wounds require careful treatment to prevent them from going deeper and to stop new tunnels from forming. Otherwise, more tissue will be destroyed and infection can spread, leading to further complications. They can even become life threatening.

This type of wound must be monitored until it’s fully healed.

Several things can contribute to the formation of a tunneling wound. There are also a few conditions that can make you more susceptible.

Stalled healing

Tunneling can happen when the wound remains inflamed too long. Other factors that can slow healing include:

Conditions that can slow healing include:


When a wound becomes infected, it can destroy tissue. Factors that may increase your risk for infection include:

  • prolonged use of antibiotics, which can also lead to secondary antibiotic-resistant infections
  • improper wound care
  • diabetes, which can cause nerve damage and impair blood flow


If concentrated where tissue layers meet, opposing forces and pressure on a wound can cause separation and tunneling.

Wound dressing

It takes careful examination to pack a wound correctly. Too much packing can dehydrate the wound and degrade tissue. Too little packing may not be absorbent enough. You should monitor and periodically adjust packing.

Hidradenitis suppurativa

Hidradenitis suppurativa is a skin condition in which small lumps form under the skin, especially where skin rubs together, such as the armpits and buttocks. Tunnels can form under the lumps.

The exact cause isn’t clear, but it may involve hormones, genetics, and immune system problems. It’s more common in women than men and tends to appear in people 18 to 29 years old.

Pilonidal cyst

These cysts form in the crease of the buttocks. They’re fairly common and can happen once or become recurrent. Untreated, pilonidal cysts can lead to tunneling.

Men get them more often than women, and they tend to form between puberty and age 40. Other risk factors include sitting a lot, being overweight, or having thick body hair.

Knowing the cause of a tunneling wound helps determine the treatment. A tunnel can curve and go through several layers of tissues, so the wound must be carefully examined. Imaging tests may be necessary to understand the full extent of tunneling.

In any case, the area must be thoroughly cleaned and dead tissue removed. Careful monitoring should continue throughout the healing process.

Packing and dressing

Packing helps healing and reduces the risk of developing an abscess. It must be packed firmly enough to prevent the wound from caving in, yet without so much pressure that it causes more damage. Your doctor may periodically modify your packing as you heal.

It’s important to keep pressure off the wound as much as you can.


Medicine for tunneling wounds may include:

  • antibiotics to treat or prevent infection
  • pain medicines
  • systemic drugs and antibiotic creams (for treatment of hidradenitis suppurativa)
  • phenol injections (for treatment of pilonidal cysts)


Draining the wound helps to promote granulation tissue formation. Granulation tissue is the connective tissue that closes up a wound.

Negative pressure wound therapy

Negative pressure wound therapy decreases air pressure on the wound to reduce swelling, remove bacteria, and promote faster healing. It’s also known as vacuum-assisted closure.

Your healthcare provider will dress and cover the wound with adhesive film. They’ll then connect a drainage tube to a portable vacuum pump, which removes air pressure.

During treatment, you have to carry the pump around, and the dressing must be periodically changed. This may continue for several weeks.


Various surgical techniques may be used to remove damaged tissue, cysts, or to expose and clean tunnels.

Managing pre-existing conditions

You and your healthcare provider should treat and manage any pre-existing conditions. If you have diabetes, it’s important to check your blood sugar often.

You can’t totally prevent them, but there are a few ways to lower your risk of developing a tunneling wound. It’s important to have all open wounds checked and treated without delay.

  • Monitor and manage pre-existing conditions, such as diabetes.
  • Keep even superficial wounds clean and dry.
  • Move around, but don’t put pressure on a wound.
  • Follow your doctor’s instructions for managing and monitoring wounds.
  • Take antibiotics exactly as prescribed.

Contact your doctor if you have:

  • intense, unexpected pain
  • swelling, redness
  • discharge or foul odor from the wound
  • fever, chills, sweats

Tunneling wounds and their treatment can be uncomfortable. They’re challenging to manage and may take weeks or even months to heal. Pilonidal cysts can recur, even after you’ve fully healed.

When healing remains stalled, tunneling wounds can become life threatening. But with prompt treatment, these wounds can heal faster and be less painful.

Any wound that breaks the skin can leave a scar. The extent of the scar depends on the injury and the healing process.

A tunneling wound is one in which channels have formed beneath the top layer of skin. Several things can contribute to development of a tunneling wound, including infection and slowed healing.

The tunnels aren’t always visible, but these deep wounds are a serious concern. Determining the extent of the tunnels and quickly starting the right treatment are vital to the healing process. Incorrect treatment can lead to life threatening complications.

Tunneling wounds can take from a few weeks to a few months to heal.