Thread by @BCMIDFellowship

1/🍄#IDFungiFriday🍄
 
This is part 2 of @A_Spallonii basic med mycology #tweetorial
 
See Part 1 here…

#IDFellows #IDTwitter #IDMedED @MedTweetorials

2/Today, we'll focus on superficial fungal infections, pathogens, and treatments, specifically:

💠 Dermatophytes
💠 Tinea versicolor

3/Dermatophytes👉a label given to 3 genera that cause skin disease in humans & animals:

🔹 Trichophyton
🔹 Microsporum
🔹 Epidermophyton

📷@DocWoc71

4/These 🍄 cause pruritus/crusty debris...

♦️Lesions characterized by spreading areas of pruritus
♦️Lesions can be single/multifocal ± hair loss

Infections w/dermatophytes = tinea (Latin for 🐛)

5/Dermatophytes:

💠Originated from animals (zoophilic) and soil (geophilic)
💠Colonize/eat the outer layer of skin
💠Inflammation➡️host responds to metabolic byproducts
💠Usually don’t invade living tissues, why?👇

6/Dermatophyte infections ➡️ named based on the body area affected:

7/Tinea corporis:

♦️ Asymptomatic or itchy
♦️ Can be subtle/present for years
♦️ Very large areas may be infected

8/Leading edge of inflammation (see arrow sign) = active border of infection with the highest concentration of hyphae.

This pattern is present in all locations except with the palms and soles!

Tinea cruris, for example:

9/
Q: Patient has several months of dry scaling skin on the left hand & both feet. No amount of lotion or scrubbing has fixed it. Why?🧐

10/He needs antifungals!

Tinea of the hands and feet can appear dry and scaly.
Can be mistaken for eczema.

Typical pattern:
💠 2 hands + 1 foot
💠 2 feet + 1 hand

11/
Tinea manuum (hand)
🔹Topicals usually effective
🔹Also treat nail & foot tinea to prevent recurrence

Tinea pedis (feet)
🔹Topicals +/- systemic antifungals
🔹Treatment reduces risk for secondary bacterial infections

❗️ALWAYS LOOK BETWEEN THE TOES❗️

12/Risk factors?

🔸 Moist/macerated skin
🔸 Animals (🐕 🐈 🐄 🐑 🐖)
🔸 Infected close contact
🔸 Topical steroids
🔸 ⬇️ immune systm (diabetes, chemo)
🔸 Athletics (wrestlers)

13/Diagnosis?

🔹KOH (potassium hydroxide) wet mount of skin scraping from leading edge
🔹Fungal cultures may be necessary
🔹Wood's lamp, hair fluoresces blue/green if Microsporum canis/audouinii

14/Now let's talk about onychomycosis

💠Prevalence⬆️with age
💠T. rubrum & mentagrophytes most common

15/There are 4 patterns of onychomycosis:

1⃣Distal subungual: distal nail bed, most common

2⃣White superficial: nail not thickened, white powdery easy scrapes off

3⃣Proximal subungual: proximal cuticle

4⃣Candida: all nails, seen w chronic mucocutaneous candidiasis

16/Treatment?

Topical:
💠Ciclopirox olamine, efinaconazole, tavaborole

Systemic:
💠Daily terbinafine or itraconazole
💠x6 wks for fingers, x12 wks for toes
💠Weekly Fluconazole x6-9 mo
💠Terbinafine👎yeast onychomycosis

17/Proximal subungual onychomycosis is the most common pattern seen in patients with HIV. If you see this, screen for HIV!

#IDDailyPearl @HoustonAETC

18/Malassezia furfur👉cause of tinea versicolor

♦️More common in adolescents in warm🏝climates
♦️Broad-based, rounded patches w/white, powdery scale on trunk and upper arms
♦️KOH exam➡️“spaghetti and meatballs” pattern

19/Treatment?

Topical: Selenium sulfide lotion, ketoconazole/econazole/miconazole cream, zinc pyrithione

Systemic: Fluconazole & itraconazole

🔥Pro-tip🔥
Since fluconazole is concentrated in sweat, exercise after taking it and avoid showering for a few hours to ⬆️efficacy