Skin lesion of blastomycosis

A skin lesion associated with blastomycosis may be a raised bump, open sore, or thickened wart-like patch. Blastomycosis is an infection caused by Blastomyces, a fungus found in soil and decaying plant material.

People usually develop blastomycosis after breathing in fungal spores from the environment. The infection begins in the lungs and can then travel through the bloodstream to the skin, bones, or other organs. Rarely, the fungus enters directly through injured skin.

Blastomycosis occurs mainly in parts of North America, including areas around the Ohio and Mississippi River valleys, the Great Lakes, and the Saint Lawrence River. Activities that disturb soil, such as digging, forestry work, hunting, and camping, may increase exposure.

Many other conditions can produce similar-looking skin changes. Appearance alone cannot confirm blastomycosis.

A blastomycosis-related skin lesion often begins as a small, firm bump or pus-filled spot. It may slowly enlarge over several weeks.

The lesion may become:

• Raised, crusted, or wart-like
• An open sore with a raised border
• Red, purple, gray, or similar to your usual skin tone
• Painless or only mildly tender
• Prone to bleeding or releasing fluid

The face and limbs are common locations, but lesions can develop elsewhere. There may be one lesion or several.

Some people also have symptoms from infection in the lungs or elsewhere. These can include cough, chest discomfort, fever, night sweats, tiredness, reduced appetite, weight loss, or pain in a bone or joint. Lung symptoms may be mild or absent even when skin lesions are present.

Most persistent bumps, sores, and crusted patches are not caused by blastomycosis. Common explanations include an irritated insect bite, a minor injury, an infected hair follicle, or a bacterial skin infection. Eczema and other inflammatory skin conditions can also crust, weep, or thicken.

Less common possibilities include other deep fungal infections, tuberculosis-related skin disease, and inflammatory disorders that cause ulcers. Sporotrichosis, another fungal infection linked to soil and plants, can cause bumps that spread along the path of a lymph vessel.

Some skin cancers can resemble a sore that does not heal or a slowly enlarging warty patch. This does not mean that a persistent lesion is cancer, but it is one reason to have a changing or non-healing area examined.

If testing confirms blastomycosis, the lesion is caused by Blastomyces. In most cases involving the skin, the fungus has spread from an infection that began in the lungs.

Book a medical appointment if a lesion keeps growing, becomes ulcerated, repeatedly bleeds, or has not started healing after a few weeks. Arrange an assessment sooner if you have recently spent time in an area where blastomycosis occurs, especially after substantial exposure to disturbed soil.

You should also seek routine but prompt care if a persistent lesion occurs with cough, fever, night sweats, unexplained weight loss, or bone pain. Tell the clinician about travel, outdoor work, digging, hunting, camping, and any conditions or medicines that weaken your immune system.

Seek same-day medical care if the skin becomes rapidly more red, hot, swollen, or painful, particularly if you also have fever or pus. These findings can indicate a bacterial infection that needs prompt treatment.

Call emergency services for severe trouble breathing, blue or gray lips, fainting, new confusion, a seizure, or sudden weakness on one side of the body. These symptoms are not expected from an uncomplicated skin lesion and need immediate assessment.

A clinician will examine the lesion and ask when it began, how it has changed, and whether you have lung or general symptoms. Your travel, work, hobbies, soil exposure, and immune health can help narrow the possibilities.

Because blastomycosis can resemble bacterial infection, another fungal infection, or skin cancer, testing is usually needed. A small skin sample, called a biopsy, may be removed after the area is numbed. The sample can be examined under a microscope and sent for fungal culture, which allows the organism to grow in a laboratory.

Blood or urine antigen tests may support the diagnosis. An antigen is a substance from the fungus that can be detected by a laboratory test. These tests can sometimes react to related fungi, especially Histoplasma, so results must be interpreted with the examination and other tests.

A chest X-ray or CT scan may be recommended because blastomycosis commonly begins in the lungs, even when cough or breathing symptoms are absent.

Treatment depends on the confirmed cause. Bacterial infections, inflammatory conditions, skin cancers, and fungal infections require different approaches, so trying several creams without an assessment can delay the right care.

Confirmed blastomycosis requires prescription antifungal medicine that works throughout the body. A topical antifungal cream is not enough for this deep infection. An oral antifungal such as itraconazole may be used for mild to moderate disease. Severe infection, infection involving the brain or spinal cord, and some other circumstances may require an antifungal like fluconazole or terbinafine given through a vein.

Treatment commonly continues for months. The exact medicine and duration depend on where the infection is, how severe it is, your immune health, pregnancy status, and how you respond. Antifungal medicines can interact with other drugs and may require blood tests or medicine-level monitoring.

While waiting for an assessment, gently wash the lesion and cover it with a clean dressing if it drains or rubs against clothing. Avoid picking, squeezing, or cutting it. Do not apply steroid cream unless a clinician has advised it, because steroids like prednisone or hydrocortisone can change the appearance of some infections.

With appropriate antifungal treatment, skin lesions usually shrink and heal gradually rather than disappearing within days. Open or thickened areas may leave a scar or a change in skin colour.

Follow-up is important to confirm that the lesion and any infection elsewhere are responding. Contact the treating clinic if a lesion continues to enlarge, new lesions appear, or breathing and general symptoms worsen during treatment.

Blastomycosis can return after treatment, although this is not expected for everyone. Keeping follow-up appointments allows symptoms and test results to be reviewed over time.

Can a blastomycosis skin lesion spread to another person?

Blastomycosis is not generally passed from person to person through touching, coughing, or contact with a skin lesion. Keep a draining area covered to protect it from irritation and ordinary bacterial contamination.

Can the skin be affected without lung symptoms?

Yes. The original lung infection may cause mild symptoms or none that you notice. Lung imaging may still show changes.

Can appearance alone identify blastomycosis?

No. Blastomycosis can look like a bacterial infection, another fungal disease, an inflammatory condition, or skin cancer. A biopsy and laboratory testing are often needed.

Will the lesion heal without treatment?

A persistent lesion should not be left to heal on its own if blastomycosis is possible. Confirmed blastomycosis generally needs systemic antifungal treatment to address infection in the skin and any other affected organs.