Black fungus is a rare but very serious fungal infection that affects the nose, sinuses, lungs, eyes and sometimes the brain. It is found in the soil and is associated with decaying organic matter such as manure, vegetables and fruit. It gets its name from the black lesions it causes on the mouth and nose, and is officially named mucormycosis, or previously zygomycosis. It's come to prominence recently owing to an association with COVID-19 infection, especially in patients who have contracted the virus in India.
The fungus that causes the infection is usually harmless to people with a normal immune system. It can become dangerous to anyone who has a lowered immune system, such as people with diabetes, HIV, or those taking medications that affect the immune system such as immunosuppressants or steroids.
The symptoms depend on where the fungus has taken hold and started to cause harm. In the lungs it causes cough, fever and shortness of breath – similar to COVID-19 symptoms, to complicate things further. In the sinuses and brain, it causes facial swelling, headache, nose congestion, fevers and black lesions on the nose or mouth, which give it its name. In some cases where the infection is in the tissues of the eye, it may be necessary to remove the eyeball to save the infection from spreading.
The treatment is with anti-fungal medication. This can be given either via an intravenous drip directly into the vein or tablets by mouth. The treatment usually needs to last for many weeks to ensure the fungus is adequately treated and will not come back at a later date. The treatment also may involve surgery to cut away tissue that is too badly affected by the infection.
With the high rate of COVID-19 infections in India, there have been a large number of patients admitted to hospital. One of the evidence-based treatments for severe COVID was shown to be high-dose steroids. This has, in turn, led to a large number of patients receiving steroids, and this seems to have triggered higher numbers of black fungus cases.