Is It Skin Cancer or a Fungal Infection?

Skin cancers, whether primary or metastatic, can sometimes coexist with or even mimic fungal infections of the skin. This can lead to later diagnosis when skin cancer is mistaken for a fungal infection. The problem is even more complex for cancer patients, who are at high risk for infection and are likely to have fungal infections coexisting with their cancer. 

Dermatologist Inspecting Patient Skin Moles

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Skin Cancer May Mimic a Fungal Infection 

Diagnosing skin cancer early is an important part of successful treatment. Skin cancer is relatively common, so knowing what to look for is vital. Skin cancer is the most common form of cancer, and it’s estimated that it affects 1 in 5 people by age 70. 

When skin cancer mimics a fungal infection, it can go undiagnosed and start to spread in the body.

If you believe that you have a fungal infection of the skin, see your dermatologist. The first step is to biopsy the skin to determine the cause of the irritation. It’s important to see your dermatologist right away if you notice a sore or skin infection that won’t heal. This is a classic sign of skin cancer and should never be ignored. 

Your dermatologist may recommend several biopsies of the same area of the skin to determine if cancer is present.   

When skin cancer mimics a fungal infection and is left untreated, it can begin to spread. The longer skin cancer grows without treatment, the more difficult it is to treat. If you have noticed a new skin growth or sore, see your dermatologist. 

A Fungal Infection Can Be Mistaken for Cancer

Some fungal skin infections can resemble or mimic skin cancer. This is especially true for fungal infections that are treatment-resistant. Skin cancer often appears as a sore that does not heal. If you have a fungal infection that is not improving, it may be mistaken as early skin cancer.

A skin biopsy will be able to show which condition is causing the issue. A fungal infection on the skin is usually successfully treated with a topical antifungal treatment. An oral antibiotic may be needed for a bacterial infection on the skin.

You may experience cancer and fungal infections at the same time. Cancer treatments like chemotherapy affect your immune system and prevent it from effectively fighting infection. This raises your risk of developing a fungal infection. If you have a blood cancer such as leukemia, lymphoma, or myeloma, you have a higher risk of experiencing a fungal infection. 

How to Lower Your Risk

It may be difficult to always prevent a fungal infection during chemotherapy, but it’s possible to lower your risk. First, call your dermatologist or primary care provider as soon as you notice a new skin growth or sore. Treating the infection early will help you have a better prognosis. If your doctor prescribes an antifungal medication, take it exactly as directed. 

To avoid being exposed to disease-causing fungi, take the following steps:

  • Avoid areas with a large amount of dust, such as a construction site.
  • Stay indoors during dust storms in your area.
  • Do not come in contact with bird or bat droppings.
  • Wear gloves when gardening or working in the soil. 
  • When spending extended time outdoors in nature, opt for shoes, long pants, and a long-sleeved shirt. 

Signs and Symptoms of Skin Cancer 

Skin cancer is a visible disease, so it is important to know how to recognize it. The most common form of skin cancer is basal cell carcinoma. Basal cell carcinoma often appears as a new skin growth with some of the following characteristics:

  • A rodent ulcer
  • Round shape
  • Reddish/pinkish color
  • Could also appear the same color as your skin
  • Shiny or pearly 
  • Dips in the center
  • Raised, rolled edges
  • Wart-like growth 
  • Sometimes have blue, black, or brown areas
  • Blood vessels visible

The second most common form of skin cancer is squamous cell carcinoma. Squamous cell carcinoma appears as a new skin growth that is:

  • A scaly red patch
  • Crusted over or bleeding
  • An open sore
  • A wart-like growth 

Melanoma is the deadliest form of skin cancer, and often appears as a mole with the following characteristics:

  • A tarry, black color or multiple colors
  • Asymmetrical 
  • Jagged borders
  • Larger than a pea
  • Changes over time

Signs and Symptoms of Fungal Skin Infections 

A helpful tip to remember is that skin cancer and fungal infections often appear in different areas of the body. This is not always the case but it may help when trying to determine what is going on. Skin cancer often appears on skin that receives the most sunlight, such as the face or ears. Skin fungal infections often appear in skin folds and areas of the skin where fungus can easily grow. 

Common signs and symptoms of a fungal infection of the skin include:

  • A red rash
  • Pimple-like bumps in the hair follicles

When to Get Help 

Talk with your dermatologist any time you notice a new skin growth or sore that is not healing. It’s best to see your dermatologist for a professional skin exam once per year. 

In addition to regular dermatology appointments, schedule time each month to perform a skin check. Performing a regular skin exam is especially important if you are at higher risk of developing skin cancer. Known risk factors include:

  • Compromised immune system
  • Unprotected exposure to ultraviolet (UV) rays from the sun or tanning bed
  • History of skin cancer
  • Family history of skin cancer

The best way to spot melanoma is by keeping an eye on any skin growths that are new or changing. When checking yourself for melanoma, remember the ABCDE’s:

  • Asymmetry: When a mole or growth has two halves that do not match each other.
  • Border: A border that is jagged or undefined means your mole should be evaluated.
  • Color: Multiple colors are a warning sign of melanoma.
  • Diameter: If you notice a mole or growth that is larger than the size of a pea, it needs to be seen.
  • Evolving: Any new or changing moles should be evaluated for melanoma.

How to Perform a Skin Self-Check

The American Cancer Society recommends checking your skin once per month. Choose a well-lit room and stand in front of a full-length mirror if possible. A hand-held mirror may be helpful to have as well.

  • Facing the mirror, start at your head and move down your body. Examine your face, ears, neck, chest, and stomach. Some people may need to lift their breasts to see the skin underneath. 
  • Check all sides of your arms, as well as your underarms. Examine your hands, including in between your fingers and under your fingernails. 
  • To examine your legs and feet, it may be helpful to sit down. Look at the tops of your legs and feet, including in between your toes and under your toenails. Use a small hand mirror to see the backs of your legs. Keep the hand mirror out to check your buttocks, genital area, and back. 
  • To check your scalp, use a comb to divide sections of hair.

If you notice a new or changing skin growth that concerns you, call your doctor and schedule an appointment right away. If you are unable to see the doctor quickly, take pictures and write down the date. 

When you see the dermatologist, they will closely examine the skin growth and ask several questions, including:

  • When did you first notice the growth?
  • Is it painful or itchy?
  • Does it ever bleed or ooze over?
  • Do you have a history of skin cancer?
  • Do you have a history of unprotected exposure to the sun or tanning bed?
  • Have you ever had a bad sunburn?

Our skin’s microbiome is made up of billions of viruses, fungi, and bacteria living on the surface. These microorganisms are usually helpful and do not need to be treated. They are responsible for preventing skin infections and keeping your skin healthy. 

However, when these microorganisms overgrow or get out of balance, an infection can occur. 

Summary

Skin cancer and fungal infection of the skin can sometimes mimic each other and make diagnosis difficult. This is dangerous because the longer skin cancer progresses without treatment, the more difficult it is to treat and cure.

It is helpful to know the signs and symptoms to look for with both conditions. For example, a fungal infection often appears in a skin fold such as the buttocks or between the toes. In contrast, skin cancer is more likely to occur in an area of the body that receives the most sunlight, such as the face or ear. 

A Word From Verywell

Trying to tell the difference between skin cancer or fungal infection is confusing. Don’t feel that you need to be an expert in this situation. If you are unsure what is causing your new skin growth or sore, see your dermatologist. They will be able to closely examine your skin and perform a skin biopsy as needed. 

Frequently Asked Questions

  • What can be mistaken for skin cancer?

    Many skin conditions can be mistaken for cancer. Skin infections caused by fungus or bacteria may mimic signs of skin cancer. If you have been treating a skin infection but do not notice an improvement, see your dermatologist. 

  • How long can you have skin cancer without knowing?

    Each case of skin cancer is unique, and its appearance will differ from person to person. It is possible to live with skin cancer for quite a while, especially if the skin growth does not appear to be changing or growing. If you notice a new growth or sore that does not seem to heal, see your dermatologist to be evaluated. 

  • What does fungus on the skin look like?

    When the fungus on the skin leads to a fungal infection, it often appears as a red, itchy rash. The rash usually appears in a skinfold, the buttocks or genitals, or other areas where fungus can thrive. A hair follicle with a fungal infection may look like a pimple. 

  • What causes fungal skin infections?

    Fungal infections occur when the normal microbiome on the skin gets out of balance. When the fungus on the skin overgrows, a fungal infection can develop. 

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8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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