Black fungus

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 – often similar to COVID-19 symptoms. 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 such as amphotericin B, posaconazole, or isavuconazole. 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.

When large numbers of patients with COVID-19 were admitted to hospital in India, one of the evidence-based treatments for severe COVID was shown to be high-dose steroids. This in turn led to a large number of patients receiving steroids, and it was this that seemed to trigger higher numbers of black fungus cases.