Medicosnext
Fungi are ubiquitous. They thrive outdoors in soil, on plants and animals, indoor damp surfaces, and on human skin. There are more than 300 fungi species known that can affect humans, ranging from non-threatening superficial skin infections to invasive critical illness commonly affecting the brain, lungs, and eyes.
Dark, warm, and humid environment provides ambient conditions for fungal growth. Regular usage of communal bathroom, swimming pool, and gymnasium; wearing moist clothes for too long, simple acts like feeding birds and close contact with bird and bat droppings, gardening, thorn prick, or excursion to caves can predispose an individual to fungal infection. Weakened immune response, either due to diseases such as diabetes, HIV, autoimmune disorders, and immunosuppressant medication, can increase the risk for primary as well as an opportunistic fungal infection. Fungal infections such as dermatophytosis, sporotrichosis, etc. are pandemic; whereas few fungal infections are endemic in certain areas. For example, coccidioidomycosis is more prevalent in southwestern America and parts of Mexico, and mycetoma typically in rural regions of Africa, Latin America, and Asia. With a growing trend of travel, it is worthwhile for patients and physicians to elaborate on the travel history and activities undertaken. Think of possible fungal infection when health deteriorates despite being on antibiotics.
Fungal infection can affect one area (localized) or many areas of the body (systemic). Systemic can be further primary or opportunistic. Primary fungal infection can occur in people with normal immune responses, sometimes with catastrophic consequences, for example, histoplasmosis, blastomycosis, coccidioidomycosis, and paracoccidioidomycosis. As mentioned above, these infections are seen commonly in certain parts of the world and are rare in other zones. They may begin as flu or pneumonia-like symptoms, and if proper treatment is delayed, may lead to multi-system disorder.
Because opportunistic fungal infection takes over weakened immunity, it is commonly seen in individuals with a weakened immune response, such as AIDs, uncontrolled diabetes mellitus, and those taking immunosuppressants. These infections are seen all over the world and can be aggressive, resulting in death affecting multisystem. It includes aspergillosis, candidiasis, and mucormycosis.
Localized fungal infection sometimes occurs when the normal balances that keep infection at bay are upset. It typically involves the skin, hair, nails, oral cavity, and external genitalia. Skin fungal infection can be superficial and deep (subcutaneous) type. Superficial skin fungal infection is commonly known as tinea, or ringworm, and appears as an itchy reddish scaly circular lesion, whereas intertriginous areas may be macerated and even foul-smelling, such as in-between toes or underneath the breast. Another variety of skin fungal infection known as pityriasis versicolor looks like either hypopigmented or hyperpigmented circular scaly patches on the trunk, neck, and rarely, cheeks. It is usually asymptomatic, but very rarely it can also itch. Tineacapitis, a fungal hair infection, presents with broken hair or scaly bald patches. It is more common in children than in adults. Onychomycosis, a fungal nail infection, looks yellowish or blotchy whitish, thickened but brittle, with powdery undersurface. Subcutaneous mycoses are sporadic and contracted in the tropics and subtropics. They may cause chronic disability, and are best diagnosed with histopathology. The commonest subcutaneous mycoses are sporotrichosis, mycetoma, and chromoblastomycosis.
Wide varieties of topical and systemic antifungals are available for the treatment of fungal infection. It is recommended to apply antifungal to an inch outside the fungally affected area, and continue applying two weeks post complete resolution of the skin lesion, to achieve a mycological cure and prevent relapse post-treatment. Topical antifungal is also available in combination with a steroid, but they are more expensive and less effective than a single agent anti-fungal. Fungal infection usually relapses after the discontinuation of the steroid-based antifungal, so people tend to reapply longer than the recommended duration. It is not uncommon to see steroid-induced side effects, such as atrophy, telangiectasia, stretch marks, super-infection, and acne. Hence, its use is discouraged by a dermatologist.
Over-the-counter antifungal is half the prescription strength and can be used for the prevention of recurrence. Laser treatment is available for resistant fungal nail infection, but the data is not compelling enough to worry about whether they are cost-effective. Only anecdotal evidence is available for home remedies, including bleach soaks and Vicks VapoRub, and some of these cures may have occurred in patients who probably never had onychomycosis.
True to the old dictum, “prevention is better than cure”, undertaking certain measures can prevent re-infection of the superficial fungal infection. Keep your skin and feet clean and dry. Many people get it wrong and skip moisturizer when we say “dry” in the context of fungal infection. Here, we mean free from moisture. Wearing non-breathable footwear and sweat or rain water-soaked clothing for too long helps fungus to grow. Sunlight doesn’t reach the inner surface of footwear, so drying it with a hairdryer is more feasible. Always wear footwear in gyms, locker rooms, and pools. Don’t share clothing, towel, hairbrushes, helmet, or other personal care items. Such items should be thoroughly cleaned and dried after use at regular intervals.
Anti-microbial resistance is a global threat, and anti-fungal resistance is no exception. A variety of reasons may account for this resistance. For example, antibiotics can reduce good and bad bacteria in the gut, which creates favorable conditions for an opportunistic fungus like Candida to grow. Resistance can develop from improper antifungal use. In our context, the triple combination of steroid, antibiotic, and antifungal, or many prescription-strength topical antifungals are available to patients without prescription from the pharmacies. Dosages too low, or treatment courses not long enough, or use of antifungal when it is anything but a fungal situation, lead to increased resistance. According to the literature, resistance is also due to the use of fungicides that treat human diseases being rampantly used in agriculture to prevent and treat fungal diseases in the crop. The superficial fungal infection had been fairly easy to treat with a basket of antifungals. As a dermatologist, we are observing the rise in the number of patients with recalcitrant fungal infection. It is not rare that we encounter look-alike fungal infection. In such a case, performing tests, such as the potassium hydroxide test, skin histopathology with PAS stain, and fungal culture, may help establish the diagnosis. Cases are not always straightforward, and it would be an interesting academic conversation about when it might be best to perform a KOH preparation versus fungal culture versus polymerase chain reaction (PCR) technology versus empiric therapy.
