Post-COVID Oral Infections: Black Fungus and More

COVID-19 had a huge impact on health beyond affecting the lungs. One of the major concerns is the rise of oral infections after COVID.

During the pandemic, we witnessed black fungus gaining attention due to its aggressive nature. Though it is one of the common post-COVID infections, there are others you should be aware of.

Why oral infections develop after COVID?

Post-COVID patients were more susceptible to oral disease due to several factors:

• Lowered immunity due to infection or corticosteroid treatment.
• Higher blood sugar levels, more so in diabetics, increase the risk of having fungal infections. Reports show that almost 80% of black fungus cases had pre-existing diabetes¹.
• The use of prolonged antibiotics, hospital stays, and oxygen therapy can also disturb the oral and systemic balance.
• Neglected oral hygiene during the infective stage can also predispose to infections.

Here are common post-covid oral infections:

1. Mucormycosis (Black Fungus)

• Black fungus can appear in the form of painful ulcers commonly in the palate, black necrotic tissue, facial swelling, loosened teeth, or can involve the sinuses. 
• Uncontrolled diabetics, patients on long-term steroids, and immunocompromised people are at a higher risk².
• The cases of black fungus need to be treated as an emergency. Immediately refer the patient to a specialist. Early antifungal therapy, like amphotericin B and surgical debridement, can be lifesaving in such cases.

2. Oral Candidiasis

• Oral candidiasis exhibits white plaques that can be wiped, erythematous mucosa, or angular cheilitis.
• It may happen due to antibiotics, dry mouth, steroid inhalers, or poor glycemic control.
• There was a significant increase in invasive fungal infections in COVID-19 patients due to immunosuppression or pre-existing health issues like diabetes.
• Mortality rate due to invasive candidiasis was around 19% to 40%, which increased to around 70% in ICU patients³.
• Topical antifungals are usually helpful. Patients with dentures should be informed about denture hygiene and reminded to soak and clean prostheses overnight. Severe or persistent cases may also need systemic antifungals⁴.

3. Herpes Simplex Reactivation

• It presents as painful vesicles or ulcers on lips, palate, or gingiva, that are often reactivated after immune stress⁵.
• Antivirals can provide symptomatic relief. If lesions are severe or atypical, it is important to refer the patient.

4. Periodontal and Opportunistic Infections

• Periodontal flare-ups are commonly seen during recovery due to reduced immunity and poor hygiene.
• Opportunistic infections like actinomycosis may also develop in necrotic tissues.
• The risk of severe COVID-19 symptoms was almost 3.25 times higher in patients with severe periodontal diseases when compared to milder cases⁶.
• A dentist should provide debridement, prescribe antibiotics if required, and reiterate the importance of oral hygiene maintenance.

Documentation and follow-up

• A dentist should always note lesion size, site, and onset relative to COVID recovery
• Don’t forget to click clinical photos to monitor changes in every visit.
• Recommend consistent follow-up visits for immunocompromised patients as the condition can deteriorate rapidly.

Red flags 

• Black, necrotic patches on palate or maxilla.
• Fast-spreading swelling or mobile teeth.
• Ulcers persisting longer than three weeks.
• Severe pain, fever, or systemic illness with oral lesions

Final Takeaway

The pandemic highlighted mucormycosis, but a dentist should be aware of the wider range of post-COVID oral infections. Being aware of common infections can help dentists recognise early signs and refer the patient when required.

References 

1. Singh AK, Singh R, Joshi SR, Misra A. Mucormycosis in COVID-19: A systematic review of cases reported worldwide and in India. Diabetes Metab Syndr. 2021 Jul-Aug;15(4):102146..
2. Ghalwash D, Abou-Bakr A, El-Gawish A. Comorbidities and final outcome of post COVID-19 associated oral mucormycosis patients: a cross-sectional study. Egypt J Otolaryngol. 2024 May 3;40:51.
3. Jain A, Taneja S. Post-COVID fungal infections of maxillofacial region: a systematic review. Oral Maxillofac Surg. 2021 Oct 7;26(3):357-63.
4. Bhujel N, Zaheer K, Singh RP. Oral mucosal lesions in patients with COVID-19: a systematic review. Br J Oral Maxillofac Surg. 2021 Nov;59(9):725-731.
5. Shanshal M, Ahmed HS. COVID-19 and Herpes Simplex Virus Infection: A Cross-Sectional Study. Cureus. 2021 Sep 16;13(9):e18022.
6. Sari A, Dikmen NK, Nibali L. Association between periodontal diseases and COVID-19 infection: a case–control study with a longitudinal arm. Odontology. 2023 Mar 3;111(4):1009–17.