Mold, yeast and other fungi are common in the environment – on surfaces, in the air we breathe, and even in our nose and sinuses. For people with allergies to mold, a wet or windy day can be miserable. Emergency rooms have recorded an increase in asthma attacks just before a thunderstorm – the approaching weather stimulates mold in the ground to release spores into the wind. In 1999, a widely publicized Mayo clinic study demonstrated that 96% of patients with chronic sinusitis have fungal elements in the sinus mucous, and proposed that most cases of chronic sinusitis were caused by the release of major basic protein from the eosinophilic white blood cells, damaging the sinus tissue while trying to eradicate the fungus. Subsequent studies failed to replicate the initial Mayo clinic findings, and later proved that almost all sinuses – healthy or not – have traces of fungi.
Most commonly caused by the fungus Candida albicans, yeast infections can be red, itchy and painful. In healthy individuals, yeast infections occur during treatment with antibiotics and steroids. The truth is, our bodies are never sterile. For example, our digestive tract normally holds about 2 to 5 pounds of normal bacteria, which we need to break down the food we eat. Even in the healthy nose, there is a balanced ecosystem of harmless bacteria and fungi, called a microbiome. Unfortunately, antibiotics kill both commensal bacteria (healthy ones) and pathogenic bacteria (those that cause disease). However, fungi are not sensitive to the antibiotics that kill bacteria, and can quickly multiply in the absence of competition. When antibiotics are taken by mouth, a yeast infection can occur in any dark, moist part of the body – including the sinuses, the mouth (thrush), the vagina, and the ear canal.
Patients with chronic sinusitis and nasal polyps often accumulate years of stale mucous in the larger sinus cavities. Saprophytic fungi (those that live on dead or decaying matter) will grow in the sinus and live on the mucous and dead cells that become trapped in the cavity. They do not attack the living tissue, but may create an inflammatory response that perpetuates the swelling and the growth of nasal polyps. Antibiotics and medications for ordinary yeast infections have no effect on fungus balls, which cause chronic nasal congestion and postnasal drainage. The fungus balls can often be seen on CT scans, and confirmed with magnetic resonance imaging (MRI). The only treatment is surgical cleaning of the sinus with removal of the polyps and debris. Usually, this is performed during endoscopic sinus surgery, although we have had occasional success in the office with transantral balloon dilation.
Allergic Fungal Sinusitis
Patients with distinct allergies to fungus may accumulate mold in the sinuses that perpetuates the allergy. Imagine scrubbing all the mildew out of your bathroom, while walking around with it growing in your sinus! The chronic exposure creates nasal polyps, asthma, and a very thick mucous, with the consistency of denture adhesive or chewing gum stuck in a shag carpet. As with a fungus ball, thorough cleaning usually requires large openings created during endoscopic sinus surgery. In addition, allergy testing and immunotherapy are recommended to calm the allergic response.
Invasive Fungal Sinusitis
It is rare for fungi to attack living tissue, but this can occur in patients who are debilitated or immune compromised, such as those with advanced AIDS, poorly controlled diabetes, or advanced cancer requiring chemotherapy. The fungi cause thrombosis (blood clots) that lead to tissue death, and then they live on the dead tissue. Although rare, this is a serious condition that can destroy the eye and the brain. Treatment requires aggressive surgery to remove all damaged tissue and intravenous antifungal medications.