Fungal Skin Infection

The protocol for Fungal Skin Infections:

Fungal Skin Infection


Let’s break it down!

Not all fungi cause infections, but the most common ones are caused by yeasts, such as Candida and Malassezia furfur, or dermatophytes, such as Epidermophyton, Microsporum, and Trichophyton.  For our purposes, this isn’t super critical information, but I think it’s important to understand that not all fungi are bad.  In fact, there are even some fungi that live naturally in our body and along the surface of our skin.  Fungi are everywhere and most of them are harmless…until they’re not.

When they begin to multiply and overwhelm the skin, an infection is produced.  They tend to thrive in warm, moist environments.  So when sweaty feet stay locked inside hot boots for long periods of time, these pesky microorganisms generously reproduce and cause an infection of the epidermis (outermost layer of the skin).  

Globally, up to 20% of people may actively be suffering from a fungal skin infection. Soldiers are at a particularly high risk of acquiring a fungal skin infection when operating in austere environments due to the lack of hygiene and exposure to animals and soil. If you haven’t already treated a patient with a fungal infection or experienced one yourself, you will at some point!

Below is a more in-depth review of fungal skin infections:


The only definitive way to diagnose a fungal skin infection is to take a sample from the affected area (whether it be a skin scraping, nail clipping, plucked hair, etc.) and examine it under a microscope.  Since equipment like that is out of the question for the majority of medics, we have to make a diagnosis mostly by physical examination and good clinical judgment. 

Fungal infections have a very unique look to them. They’re scaly, erythematic (red), and have well-demarcated borders that are generally circumferential in shape. This picture below show’s a good example:

Pictures of Fungal Sin Infections

There are plenty of other dermatological complaints that look like this though, so be humble in your diagnostic certainty. Fungal skin infections are quite frequently confused with Contact Dermatitis, which is an inflammation of the skin caused by an allergen or irritant. You have to be careful in your diagnosis because if you treat a fungal infection with steroid creams like you would with contact dermatitis, you can exacerbate the infection. 

And yes!  You’ve probably been hearing slang terms for fungal skin infections you’re whole life:

    • Feet = “Athletes foot” (Tinea Pedis)
    • Groin = “Jock itch” (Tinea Cruris)
    • Torso/Extremities = “Ringworm” (Tinea Corporis)

Antifungal medications for a fungal infection….too easy.  If you’re looking in your med box for antifungals, you can easily identify most of them by the “azole” at the end of their generic names (except for Terbinafine).

For the most part, antifungal creams like Clotrimazole are going to be our first-line agents.  Once it’s absorbed through the skin, it targets the membranes of the fungi and “pokes holes” across it; essentially killing the fungi and clearing the infection.

Simple, isolated fungal infections will respond pretty well to this, but fungi are notorious for reinfecting hosts after the initial infection.  That’s why the protocol specifically states to continue applying the creme for ONE WEEK AFTER the lesions disappear; so that we can prevent this from reoccurring


For those moderate to severe cases (which one might define as finding evidence of a more systemic fungal infection or a persistent skin infection that’s not going away with creme alone), we’re going to give an ORAL antifungal, like Fluconazole  

Fluconazole is a synthetic triazole antifungal agent that typically comes in a packs of 1 to 4 capsules. The patient simply has to take 1 pill per week and watch the magic happen. There may be times when longer treatment is needed, but a two-week treatment will work for most infections. Keep in mind that there is a higher potential for side-effects in oral anti-fungal agents than cremes.



Evacuation for a fungal infection is seldom required, but keep in mind that if the patient is not responding to any of your treatments, you may need to reconsider your differentials.  If it’s NOT a fungal skin infection, it could be something that DOES require an evacuation.


Good luck out there!


Brandon Simpson, PA-C
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