Black Fungus: Causes, Symptoms, and Prevention Tips

July 6, 2025

What is Black Fungus?

Black fungus, medically known as mucormycosis (sometimes called zygomycosis), is a rare but serious fungal infection caused by molds called mucormycetes. These molds are widespread in the environment, present in soil, decaying leaves, compost, and even in the air we breathe. Most people come into contact with them daily without falling ill.¹

However, in people with weakened immune systems, these fungi can cause aggressive infections that progress quickly and may turn fatal without timely treatment. Black fungus became widely known during the COVID-19 pandemic, especially in countries like India, where many immunocompromised patients developed the infection following steroid use or oxygen therapy.²

Depending on how the spores enter the body, mucormycosis can affect the sinuses, lungs, skin, and gastrointestinal tract, or even spread to the brain. It is one of the most common mold-related infections reported in hospital settings and requires urgent antifungal treatment.³

India is one of the countries with the largest spread of the disease. There are two major reasons for this:

In India, there are a high number of people with diabetes, and diabetics are the most vulnerable group to this disease.⁴
Because of high humidity, which leads to an increase in the spread of fungi.

Illustration showing different forms of mucormycosis, including sinus infection, brain involvement, lung infection, skin necrosis, and the fungus Rhizopus species at the center, which is responsible for the disease. — Mucormycosis (Black Fungus): A rare but aggressive fungal infection affecting the sinuses, brain, lungs, skin, and bloodstream—commonly seen in immunocompromised individuals.

Causes of Black Fungus

Mucormycosis is caused by fungi belonging to the order Mucorales. Among these, Rhizopus oryzae is the most commonly implicated species and also the most aggressive. Other genera involved include Mucor, Lichtheimia, Apophysomyces, Cunninghamella, Saksenaea, and Mortierella, though some of these are less common.⁵

These molds are widely present in the environment, and their spores can be found in soil, compost, decaying organic matter, and even in the air. In some cases, spores may contaminate foods such as spoiled fruits or bread. Infection occurs when these spores enter the body through different routes:

Inhalation is the most common, particularly affecting the sinuses and lungs.
Direct skin inoculation can happen through cuts, burns, or surgical wounds.
Ingestion of contaminated food may lead to gastrointestinal mucormycosis.
Contaminated medical devices or wound dressings have also been reported as rare sources, especially in healthcare settings.⁶

In hospital environments, outbreaks have been linked to contaminated linens, poor ventilation, ongoing construction, and unclean medical equipment, especially in patients with compromised immunity.

Once inside the body, the fungal spores can germinate and form broad, ribbon-like hyphae that invade blood vessels. This leads to vascular thrombosis, tissue infarction, and necrosis, which are hallmark features of this aggressive infection.

Microscopic view of black fungus spores — Mucor mold, also known as black fungus

Who is at Risk?

Many of the black fungus cases started showing up in patients who had recently recovered from COVID-19, especially those with other health problems like diabetes, kidney disease, or cancer. One big factor seems to be the use of steroids during COVID treatment, which can weaken the immune system just enough to give the fungus a chance.

The reason is their compromised immune system, leading to this deadly infection. Mucormycosis is more common in people with HIV/AIDS, congenital bone marrow disease, viral diseases, malignancies, and people with severe burns.
Injected drug use and high levels of iron in your body (hemochromatosis). People with poor health from poor nutrition and those with unhealthy levels of acid in their body (metabolic acidosis) as well as premature birth babies.

Signs & Symptoms

The symptoms of mucormycosis vary depending on the area of the body that’s affected, but the infection usually progresses quickly and can become severe if not treated promptly. People may experience:

Nasal congestion, sinus pain, or nosebleed
Blackish or bloody discharge from the nose
Swelling around the eyes, drooping eyelids (ptosis), or eye inflammation
Blurred or double vision, eye pain, and in some cases, vision loss
Facial swelling or numbness, often on one side
Headache and fever
Persistent coughing, sometimes with blood
Difficulty breathing or shortness of breath
Nausea or vomiting, occasionally with blood (especially in gastrointestinal cases)
Altered mental status or confusion if the brain is involved
Painful skin lesions, ulcers, or discolored patches that may turn black
Blood clotting issues that can lead to tissue death or skin necrosis

Recognizing these symptoms early is essential, especially in people with compromised immune systems. The infection can rapidly worsen and requires urgent medical treatment.

Types of Mucormycosis

Mucormycosis can present in different forms depending on where the fungus spreads in the body. Each type tends to affect people with specific risk factors, and the severity can vary widely.

Rhino-Orbital-Cerebral Mucormycosis:

This is the most common form, usually seen in people with uncontrolled diabetes or recovering from COVID-19. It begins in the sinuses and can spread to the eyes and brain, often presenting with facial swelling, vision changes, or neurological symptoms.⁷

Pulmonary Mucormycosis:

Involves the lungs and is more frequent in patients with hematologic malignancies, prolonged neutropenia, or transplant recipients. It can be mistaken for bacterial pneumonia, but it progresses rapidly if not treated early.⁸

Cutaneous Mucormycosis:

Occurs when spores enter through the skin, usually after trauma, surgery, or burns. It may start as redness or swelling at the site but can invade deeper tissues if untreated. This form can also occur in otherwise healthy individuals.

Gastrointestinal Mucormycosis:

Less common and typically affects premature infants or immunocompromised adults. It involves the stomach or intestines and may present with nonspecific abdominal symptoms or GI bleeding.⁹

Disseminated Mucormycosis:

This severe form occurs when the infection spreads through the bloodstream to multiple organs, most commonly the brain. It is most often seen in critically ill patients and carries a high risk of mortality

Diagnosis of Black Fungus (Mucormycosis)

Timely diagnosis of mucormycosis is critical due to its aggressive nature and high mortality in immunocompromised patients. A combination of clinical suspicion, imaging, laboratory evaluation, and histopathology is used for confirmation.

Clinical Assessment:

A focused history and examination should include:

Recent illness (e.g., COVID-19), steroid use, diabetes, or other immunosuppressive conditions
Facial pain, nasal congestion, or black discharge
Symptoms involving the eyes, lungs, skin, or CNS
Inspection for necrotic lesions, swelling, proptosis, or skin ulcers

Physical exam findings may show:

Black eschar on the nasal mucosa or palate
Facial asymmetry or orbital swelling
Visual changes or cranial nerve deficits
Lung findings (in pulmonary involvement) such as rales or hypoxia

Laboratory Investigations:

Complete Blood Count (CBC): May show leukocytosis or neutropenia
Blood glucose levels: To check for uncontrolled diabetes
Renal function tests: Important before antifungal therapy (e.g., Amphotericin B)
Inflammatory markers: CRP and ESR may be elevated

Microbiological & Histopathological Testing:

Direct KOH mount or fungal stain from a nasal or tissue swab shows broad, aseptate hyphae
Culture on Sabouraud dextrose agar (low yield, slow-growing)
Histopathology (biopsy): Gold standard; shows angioinvasion and tissue necrosis

Imaging Studies:

Imaging helps define the extent of spread, especially in rhino-orbital-cerebral cases:

Modality	Findings
CT scan (PNS or chest)	Bone erosion, sinus opacification, lung nodules, or cavitations
MRI with contrast	Orbital or brain involvement, perineural spread
X-ray (chest)	Pulmonary infiltrates in lung involvement

Treatment of Black Fungus

Mucormycosis is a medical emergency and needs to be treated without delay. The treatment usually involves a combination of antifungal medications and surgery.

The most commonly used antifungal drug is Amphotericin B. It works by targeting a substance called ergosterol in the fungal cell membrane, damaging the membrane and killing the fungus. This medicine is given through a vein and is usually continued for several weeks, depending on how the patient responds. In some cases, treatment may need to go on for several months.

If the infection has caused tissue damage, surgical debridement is often necessary. The goal is to remove all the dead or infected tissue before the fungus can spread any further. This can involve removing parts of the sinuses, jaw, or even the eye in severe cases. While this may sound drastic, it’s sometimes the only way to save the patient’s life.

Other antifungal drugs like isavuconazole and posaconazole may also be used, especially if Amphotericin B cannot be tolerated due to kidney problems or side effects. These drugs also work by interfering with the fungal cell membrane.

In some situations, doctors may also use hyperbaric oxygen therapy. This involves breathing pure oxygen in a special chamber to help the body fight off the infection and support tissue healing. It may help white blood cells work more effectively against the fungus.

Because the treatment can be intense and prolonged, patients are usually cared for by a team of specialists, including infectious disease doctors, surgeons, and critical care experts.

Complications of Black Fungus

The Complications of mucormycosis include

Blindness because of eye infections
Blood clots or blocked vessels
Nerve damage

These complications show that mucormycosis can be deadly without treatment. The likelihood of death depends on which part of the body is affected. People who have sinus infections are more likely to survive than those with lung or brain infections.

How can you prevent it?

Mucormycosis is deadly but it surely is preventable. Several steps can be taken to prevent being infected by fungi. These include:

Ensuring personal hygiene by bathing and scrubbing the body thoroughly. This is to be done particularly after returning home from work, working out, or visiting neighbors, relatives, or friends.
Wearing face masks and face shields when you’re going to dirty polluted environments such as construction sites.
Make sure to wear fully covered clothes along with concealed shoes, long pants, long-sleeved shirts, and gloves when you’re coming in contact with soil, moss, or manure, like in gardening activities.

Conclusion

Mucormycosis is a rare disease but poses an important burden on immunocompromised patients. Antifungal medications have been of great help in fighting against the disease, but it’s always better to prevent than cure the disease. It is spread when exposed to places where there are soil plants and manure. Special care needs to be taken there like wearing gloves and masks. Even if infection does occur after all the preventive measures, diagnosis has become easier through CT scans, tissue biopsy, and MRI, despite the fact that it takes a little longer for examination.

Refrences

1
Centers for Disease Control and Prevention. (2023, October 13). Mucormycosis. CDC. https://www.cdc.gov/fungal/diseases/mucormycosis/index.html
2
Hoenigl, M., Seidel, D., Carvalho, A., Rudramurthy, S. M., Arastehfar, A., Gangneux, J. P., … & Cornely, O. A. (2022). The emergence of COVID-19-associated mucormycosis: Analysis of cases from 18 countries. The Lancet Microbe, 3(7), e543–e552. https://doi.org/10.1016/S2666-5247(21)00172-2
3
Cornely, O. A., Alastruey-Izquierdo, A., Arenz, D., Chen, S. C., Dannaoui, E., Hochhegger, B., … & Mellinghoff, S. C. (2019). Global guideline for the diagnosis and management of mucormycosis: An initiative of the European Confederation of Medical Mycology in cooperation with the Mycoses Study Group Education and Research Consortium. The Lancet Infectious Diseases, 19(12), e405–e421. https://doi.org/10.1016/S1473-3099(19)30312-3
4
Prakash, H., & Chakrabarti, A. (2021). Epidemiology of mucormycosis in India. Microorganisms, 9(3), 523. https://doi.org/10.3390/microorganisms9030523
5
Spellberg, B., Edwards Jr, J., & Ibrahim, A. (2005). Novel perspectives on mucormycosis: Pathophysiology, presentation, and management. Clinical Microbiology Reviews, 18(3), 556–569. https://doi.org/10.1128/CMR.18.3.556-569.2005
6
World Health Organization. (2021, May 26). WHO urges countries to step up surveillance for mucormycosis. https://www.who.int/news/item/26-05-2021-who-urges-countries-to-step-up-surveillance-for-mucormycosis
7
Shah, K. S., Bhatt, J. B., Rawal, R. M., Dohadwala, Z. S., Shah, S. N., & Patel, K. G. (2023). An analysis of the presentations of rhino-orbital mucormycosis amidst the COVID pandemic: A case series report. International Journal of Medical Research & Health Sciences, 12(3).
8
Agrawal, R., Yeldandi, A., Savas, H., Parekh, N. D., Lombardi, P. J., & Hart, E. M. (2020). Pulmonary mucormycosis: Risk factors, radiologic findings, and pathologic correlation. Radiographics, 40(3), 656–666. https://doi.org/10.1148/rg.2020190156
9
Tormane, M. A., Laamiri, G., Mroua, B., Gazzah, H., Beji, H., Zribi, S., & Touinsi, H. (2023). Gastric mucormycosis: A case report and review of the literature. Clinical Case Reports International, 7(1), Article 1603. https://doi.org/10.25107/2638-4558.1603

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