Fungal Skin Infections: Skin Anatomy, Pathophysiology, and Risk Factors (Nursing)

00:00 Hi, I'm Dr. Rhonda Laws, and today we're going to explore fungal skin infections and how we treat them.

00:07 So by the end of this series, you'll understand how these medications work and how you can safely administer them to your patients.

00:14 Remember, everything you learn connects directly to patient care and safety.

00:19 So I want to start with the big picture and then we'll drill down to the details.

00:23 Now I know you already know that skin is our largest organ, and it serves as a protective barrier.

00:28 So in this part, we're going to build on that foundation to help you understand how fungi can breach this barrier, and how our medications target these nasty invaders.

00:39 So let's first quickly review the skin structure so that we all are on the same page about what we're protecting.

00:45 Now remember, our skin has three main layers.

00:48 Take a quick pause and see if you can name those in your own mind.

00:53 First layer is the epidermis.

00:55 Now that's our outermost protective layer.

00:58 It contains the keratinocytes.

01:00 Now the keratinocytes actually produce keratin.

01:04 Now, keratin is what we want to talk about here.

01:06 Keratin is this really tough protein that helps waterproof your skin.

01:10 So think of your epidermis as the brick wall that keeps the pathogens out.

01:16 So the epidermis is on the top.

01:18 The next layer is the dermis.

01:21 Now this is the dermis that's beneath the epidermis, and it contains things like blood vessels, nerves, hair follicles, and glands.

01:27 This is like the supply network that nourishes the epidermis above it.

01:32 The third layer is the subcutaneous tissue and that's the fat layer that insulates and cushions us.

01:39 There are two key features of healthy skin that protect against fungal infections.

01:44 One is the pH and the other is the normal flora.

01:48 Now the pH is slightly acidic, usually around 4.5 to 6.5, and the normal flora that's there, it's the friendly microorganisms.

01:57 They help prevent pathogens from gaining a foothold.

02:01 So when environmental factors alter the skin's normal conditions, such as increased moisture, pH changes, or even disrupted normal flora, fungi can more easily establish infections.

02:13 That's why areas like the feet, the groin, and skin folds are particularly vulnerable to fungal infections.

02:19 Now, what happens if you change the skin's environment? What do you think might occur if skin becomes too moist or if the pH changes? Pause here and see if you can predict what the answer is.

02:32 Okay, if you guessed this, you're right.

02:36 These changes can disrupt the normal balance and create conditions where fungi can thrive.

02:40 So again, that's why areas like your feet, groin, and skin folds are particularly vulnerable to fungal infections.

02:48 The fungi that cause skin infections are primarily dermatophytes.

02:53 Now that's a word that literally means skin plants.

02:55 Now they're not actually plants, but these names will help you remember that they take root in the skin.

03:02 So when you think of dermatophytes, remember, these are taking root in the skin.

03:08 Now these fungi are specialized to invade keratinized tissues like skin, hair, and nails.

03:14 So why do you think it's just these tissues? Well, because dermatophytes feed on keratin.

03:20 They use these specialized enzymes called keratinases, right? So you see A-S-E-S on the end of keratin.

03:28 We know that's an enzyme, A-S-E, that eats keratin.

03:32 So these dermatophytes feed on this keratin by using these special enzymes called keratinases, and that's what digests the keratin.

03:40 So there's three main genera that you'll usually encounter, and I put those names on the screen for you.

03:45 You don't necessarily have to memorize those, but I wanted you to be aware of them.

03:49 So let's visualize the entire infection process.

03:53 The fungus releases keratinases that will digest the keratin.

03:57 Now it's the digestion of the keratin that will trigger inflammation, and the body recognizes the fungal invasion.

04:03 Now, as the fungi spread outward, they start to create these characteristic raised borders like you see in ringworm.

04:10 Now, how it will feel as a patient will be scaling, itching, and discomfort.

04:15 So that's a brief overview of the infection process of fungi.

04:20 So let me ask you a question.

04:22 What type of patients do you think might be more susceptible to fungal infections? Pause and see if you can come up with a quick list.

04:30 Then I'll come back and give you a complete list.

04:35 Welcome back.

04:36 Okay, so the types of patients that are more susceptible to fungal infections include patients with diabetes, those who are immunocompromised, people who frequent communal showers or pools, and those who experience excessive sweating.

04:51 These are all at an increased risk.

04:54 So it's important that you understand these risk factors because it'll help you both with prevention and treatment planning.