Mucormycosis (Black Fungus)

What mucormycosis is

Mucormycetes (such as Rhizopus, Mucor and Lichtheimia) are everywhere in the environment. People breathe in their spores daily without harm, because a healthy immune system clears them. In people with certain risk factors, the spores germinate and the mold grows into blood vessels, causing clots and tissue death (necrosis). That is why affected tissue turns black.

It is not contagious between people.

Risk factors

• uncontrolled diabetes, especially diabetic ketoacidosis (high blood sugar and acid help the fungus grow)
• blood cancers and chemotherapy causing prolonged low neutrophils (neutropenia)
• stem cell and organ transplants
• high-dose or prolonged corticosteroids
• iron overload, including treatment with deferoxamine
• severe burns, trauma and contaminated wounds (for example after natural disasters)
• injection drug use
• premature birth (gut infection in newborns)

During the COVID-19 pandemic, many cases occurred in India among people with diabetes treated with steroids for COVID-19, highlighting the danger of steroids plus poorly controlled blood sugar.

Forms and symptoms

Rhino-orbital-cerebral (most common with diabetes)

Starts in the nose and sinuses, where it can be mistaken for ordinary sinusitis, and can spread to the eye and brain within days:

• one-sided facial pain, swelling or numbness
• nasal congestion, bloody or black nasal discharge
• black lesions on the nasal bridge or roof of the mouth
• headache and fever
• eye swelling, drooping eyelid, double vision, loss of vision (resembling orbital cellulitis)
• confusion and reduced consciousness if the brain is involved

Pulmonary

Mainly in people with cancer or transplants, and similar to aspergillosis: fever, cough, chest pain, breathlessness and coughing blood.

Cutaneous (skin)

After wounds, burns or injections: a red, painful area that turns black and spreads.

Gastrointestinal

Rare; abdominal pain, bleeding, mainly in premature infants and very ill patients.

Disseminated

Spread through the blood to several organs in severely immunocompromised people.

Diagnosis

• urgent examination, including nasal endoscopy to look for dead tissue
• CT and MRI of the sinuses, eyes and brain, or chest CT
• biopsy of affected tissue, which shows the typical broad, ribbon-like fungal threads invading tissue; this is the key test
• fungal culture and molecular tests (PCR) to identify the species

Treatment should not wait for culture results when the diagnosis is strongly suspected.

Treatment

Success depends on speed and combining three elements:

1. Surgery: aggressive removal of all dead and infected tissue (debridement). This may involve sinus surgery and, in severe cases, removal of the eye or part of the jaw. Repeated operations are common.
2. Antifungal medicine: high-dose IV liposomal amphotericin B first, then step-down to isavuconazole or posaconazole, often for weeks to months.
3. Correcting the underlying condition: treating ketoacidosis and controlling blood sugar, reducing steroids and immunosuppression where possible, and supporting white cell recovery.

Outlook

Mucormycosis is life-threatening. Mortality is high, often around 40 to 50 percent across all forms, and higher with brain involvement or disseminated disease. Early diagnosis and combined treatment substantially improve survival. Survivors may have facial disfigurement or vision loss and need reconstructive surgery and rehabilitation.

Prevention

• keep blood sugar well controlled and treat ketoacidosis promptly
• use steroids only when needed, at the lowest effective dose, with blood sugar monitoring
• people with severely weakened immune systems should avoid areas with lots of dust, soil or decaying material such as construction sites, and may be given antifungal preventive medicine
• clean wounds well, especially after soil contamination

Frequently asked questions

What is mucormycosis?

Mucormycosis is a rare but serious infection caused by molds found in soil and decaying matter. It invades blood vessels and kills tissue, often starting in the sinuses or lungs, mainly in people with uncontrolled diabetes or weakened immune systems.

What are the first signs of black fungus?

Early signs include one-sided facial pain or swelling, nasal blockage, bloody or dark nasal discharge, black patches inside the nose or mouth, fever and headache. Eye swelling, drooping eyelid or vision changes mean it may be spreading.

Is mucormycosis contagious?

No. It is caught from spores in the environment, not from other people. Most people breathe in these spores without harm; infection occurs mainly when the immune system is weakened or blood sugar is very high.

How is mucormycosis treated?

It is treated with urgent surgery to remove dead tissue, IV antifungal medicine such as liposomal amphotericin B followed by isavuconazole or posaconazole, and correcting the underlying condition, especially high blood sugar.