1. Cutaneous Fungal Infections
Susan Massick, MD
OSU Dermatology
Phone: (614)
Dr. Susan Massick with the Division of Dermatology at OSUMC. Today I will be discussing cutaneous fungal infections.

2. Learning Objectives Identify and diagnose cutaneous fungal infections
Plan treatment approaches for dermatophyte skin infections
The learning objectives for this module include being able to identify and diagnose cutaneous fungal infections and to plan appropriate treatments for these infections.

3. What are Dermatophytes?
Dermatophytes: fungi that digest keratin
Geophilic: soil keratin
Zoophilic: animal keratin
Anthrophilic: human keratin
Infection limited to keratin structures
Stratum corneum
Hair
Nails
What are dermatophytes? A dermatophytes is a type of fungus which digests keratin, so these types of infections tend to be superficial with infection limited to keratin structures which can be found in the stratum corneum, superificial layer in the epidermis, hair, and nails. There are geophilic dermatophytes, which ingest keratinous debris in soil; zoophilic which ingest animal keratin, and anthrophilic which ingest human keratin.

4. Types of Dermatophyte Infections
Tinea Capitis
Tinea Corporis
Tinea Cruris
Tinea pedis and Onychomycosis
Tinea Versicolor
Common genera: Microsporum, Trichophyton, and Epidermophyton
These dermatophyte, or superficial fungal infections, are often characterized by the location of the body that is infected. During this module, I will be reviewing clinical presentation, physical exam findings, diagnostic tests, and treatment options for tinea capitis, corporis, cruris, pedis, and versicolor. Common genus families of dermatophyte infection include Microsporum, Trichophyton, and Epidermophyton. Most common of each include M. Canis, T. Tonsurans, and E. floccosum.

5. Tinea Capitis: Scalp Ringworm
Common fungal infection in children, especially African American children
Trichophyton tonsurans is most common anthrophilic organism to cause tinea capitis in U.S.
Microsporum canis is most common zoophilic organism to cause tinea capitis in U.S.
Let’s start from the top first: Tinea capitis. Tinea capitis is a dermatophyte infection of the scalp, also called Scalp Ringworm.
It is a common fungal infection, particularly in African American children. Trichophyton tonsurans is the most common anthrophilic organism to cause tinea capitis in the U.S. while M. canis is most common zoophilic organism to cause tinea capitis in U.S.

6. Clinical Manifestations of Tinea Capitis
Patches of alopecia with erythema and scaling
Small black dots
Diffuse dandruff
Kerion formation due to severe inflammation
There are several common presentations of scalp ringworm, including patches of hair loss, or alopecia, associated with redness and scaling. Small black dots with hair loss with the black dots representing infected hairs broken at or near surface of the scalp. Diffuse scaliness of the scalp. And less commonly a kerion formation which presents a severe inflammatory form of tinea capitis where there is a large boggy indurated area with swelling, tenderness, and pus associated with inflammation. The infection is based upon the fungus invading and attacking the hair shafts.

7. Physical exam: Round patchy alopecia with mild scale

8. Physical exam: Black dot formation
Black dot formation: broken hairs near surface of scalp due to dermatophyte infection, often with scale and erythema
This type of alopecia different from alopecia areta, for ex, which is smooth and shiny skin without erythema

9. Physical exam: Kerion
Kerion with indurated, swollen, pustular inflammatory lesion. Often resolves with scarring and permanent hair loss.

10. Physical exam: Diffuse scaliness
Tinea capitis is most commonly seen in African American children and can often present as diffuse scaliness associated with itchy scalp

11. Diagnosis of Tinea Capitis
Diagnosis can be established by KOH and fungal culture
Wood’s lamp can identify certain dermatophytes via fluorescence
M. canis fluorescence
T. tonsurans - fluorescence
The diagnosis of tinea capitis can be made by KOH and by fungal culture.
A KOH Prep is performed by scraping the skin onto a glass slide and adding a few drops of potassium hydroxide. KOH will dissolve keratin but not fungi because their cell walls will remain intact. In a +KOH prep, the keratin will have dissolved, leaving the fungi visible. Depending on the specific dermatophyte, the fungal hyphae or spores will be visible. Culture of the skin scraping or infected hairs can yield fungal growth when placed on agar plates.
Wood’s lamp can be used to distinguish between Microsporum and Trichophyton species, since M. Canis fluoresceses under the light and Trichophyton tonsurans does not.

12. Endothrix: Spores within the hair shaft
Fungus can either invade inside the hair shaft, which is called Endothrix, or outside the hair sheath, which is called Ectothrix. T. Tonsurans is an example of endothrix where the spores are found inside the hair shaft, as in this photo. Here you can see all the spores within the hair shaft.
Spores

13. Ectothrix: Spores outside hair sheath
Hair Shaft
This is a KOH prep of an ectothrix type of infection, where the spores are seen outside of the outer root sheath of the hair shaft. M. canis is an ectothrix type of infection.
Spores outside hair sheath

14. Wood’s lamp with fluorescence
On the left is an example of a typical presentation of tinea capitis with round patch of alopecia with scaliness: under Wood’s lamp on the right showing blue-green fluorescence, with most likely organism being Microsporum canis. While the clinical presentations of M. canis and T. tonsurans can be similar, they will differ in their KOH appearance, the pattern of growth on fungal culture, and the presence or absence of fluorescence under Wood’s lamp.

15. Treatment of Tinea Capitis
Tinea capitis must be treated with oral therapy
First line treatment: griseofulvin, which disrupts fungal microtubule formation
Other alternative oral medications include terbinafine, fluconazole, and itraconazole
Add shampoos, such as selenium sulfide, cicloprox, or ketoconazole, to decrease transmissibility of infection
Treatment for tinea capitis must include systemic therapy for complete eradication b/c the organism is deep in the hair follicle and hair shafts. First line of treatment is oral griseofulvin, whose mechanism of action include a disruption of fungal microtubule formation, often for 6-8 weeks. Other alternative medications include terbinafine, fluconazole, and itraconazole. Shampoos are an important adjunctive treatment to decrease the transmissibility of the infection, particularly among family members.

16. Tinea Corporis Also called ringworm
Red scaly ring with central clearing
May involve trunk, arms, legs, neck
Moving from scalp ringworm to ringworm on the body, the next dermatophyte infection to be covered is tinea corporis. Tinea corporis is characterized by the red scaly ring with central clearing classic appearance, which is why it is often called “ringworm.” It primarily effects the trunk, arms, legs, and neck. The most common dermatophyte species that cause tinea corporis incllude T. rubrum, M. canis (particularly from exposure to infected animals), and T. mentagrophytes. Diagnosis is made by physical exam and confirmed by KOH skin scraping. Localized infections with just a few patches may be treated with a topical antifungal agent, while systemic medications may need to be used if widespread

17. Physical exam (T. corporis): annular scaly red ring with central clearing
Picture of a classic tinea corporis presentation: red annular patch with scaling on border and clearing in center; can have more than one patch

18. Tinea Corporis: Diagnosis and Treatment
Most common fungal etiologies:
Trichophyton rubrum, Microsporum canis, and Trichophyton mentagrophytes
Diagnosis can be made by KOH exam
Can treat with topical antifungals for local disease and systemic oral antifungals, such as terbinafine or griseofulvin, if widespread

19. KOH skin scraping: Fungal filaments
Diagnosis is confirmed by KOH skin scraping where you can see fungal filaments. Other organisms will look like hyphae and spores under KOH.

20. Tinea Cruris Also known as “jock itch”
Presents as chronic brown to red patches in groin folds and upper/inner thighs
Rare before puberty, more common in men
Often spares scrotum, penile shaft, glans penis
Dermatophyte infections of the groin are called tinea cruris, which present as brown to red patches in the folds of the groin and the upper and inner thighs. Dermatophytes thrive in warm, moist environments, and certainly can flare with increased perspiration and humidity. More widely known by its nickname “jock itch” tinea cruris tends to be more common in men, although it can occur in women, and certainly more common in warm, moist environments. In male patients, the rash tends to remain in the inguinal folds with sparing of the scrotum and penis.

21. Physical exam (T. cruris): Red patch in groin with sparing of penis and scrotum
This is a typical tinea cruris presentation: male patient, red patch with clearly demarcated borders with involvement of upper and inner thighs and groin with sparing of penis and scrotum.

22. Tinea Cruris
Should be differentiated from candidiasis, which is typically bright red, often involves scrotum, glans penis, may manifest satellite pustules
Common fungal etiologies include Trichophyton rubrum, Trichophyton mentagrophytes, Epidermophyton floccosum
Usually responds to topical antifungal therapy
Tinea cruris can be mistaken for candidiasis; however, Candida infections will characteristically have involvement of the scrotum and penis along with small satellite papules and pustules. Common fungal organisms that cause tinea cruris include T. rubrum, T. mentagrophytes, and epidermophyton floccosum. T cruris respond to antifungal topical therapy although there is a high recurrence rate. Antifungal powders are helpful to minimize moisture and reucurrence.

23. Tinea Pedis Extremely common fungal infection of skin of feet
Commonly called “athlete’s foot”
Similar fungal organisms that cause tinea cruris: Trichophyton rubrum and mentagrophytes
Tinea pedis, also known as athlete’s foot, is a common fungal skin infection involving the feet.

24. Tinea pedis: Presentation and Treatment
Moccasin type causes redness and scaling of soles and sides of feet
Interdigital type produces white macerated fissures between the toes, usually 4th-5th spaces
Bullous type produces small blisters on sole of foot
Often responds to topical antifungal agents, such as topical terbinafine
There are several different types of tinea pedis, including the moccasin type, the interdigital dype, and the bullous type. Moccasin pattern t. pedis presents as redness and dry scaling on the sole and sides of the feet. Interdigital type usually presents as macerated, white fissured skin between the toes, most commonly the 4th and 5th toe webspaces. Bullous type shows small blisters or vesicobulla lesions on the sole. Treatment mainly involves topical antifungals. Like tinea cruris, t. pedis is exacerbated by warm moist environments, so helpful to minimize this.

25. Physical exam: Moccasin type T. pedis
This is a clinical picture of moccasin pattern tinea pedis with redness and scaling involving soles and sides, almost as if one is wearing a moccasin. Note also the nail involvement with fungal infection or onychomycosis of the toenails. I will be discussing onychomycosis in further detail as well but it’s important to recognize that t. pedis and onychomycosis will often occur simultaneously.

26. Physical exam: T. pedis
Interdigital t. pedis with interdigital scaling with fissuring as well as bullous lesions with resulting red/brown crust. The most common complaint with any type of tinea pedis is the associated itching.

27. Onychomycosis Fungal infection of nails, or tinea unguium
When toenails involved, often associated with tinea pedis
May produce yellow or white discoloration of toenails with dystrophy or separation of nail from nailbed
Nails may become thickened or develop white powder under the nail
Fungal etiology is similar to tinea corporis: T. tonsurans, T. rubrum
Tinea pedis is often seen in conjunction with fungal infections of the toenails. Onychomycosis is a fungal infection of the nails; while all nails can be involved, it is most frequently seen on the toenails

28. Physical exam: Onychomycosis
Physical findings seen in this clinical picture include the yellowish discoloration of the nail, the thickening and dystrophic appearance of the nail. The thickening of the nail can often lead to separation of the nail plate from the nail bed. Not all separation is from fungal infections and the color change noted with the nails can help distinguish between other types of infections.

29. Green nail: Pseudomonas infection
Not all nail abnormalities are necessarily dermatophyte infections: Here is a nail with greenish discoloration: the nail plate has separated from the nail bed at the distal portion allowing pseudomonas bacteria to set up shop, leading to the unique but characteristic greenish discoloration. Because it is a pseudomonal infection, it does not respond to topical antifungals and must be treated with antibacterial drops and diluted vinegar soaks.

30. Treatment of Onychomycosis
Usually requires systemic antifungal agents with terbenafine being most effective. Itraconazole is less effective.
Topical antifungals are less effective
Tinea pedis cannot be effectively treated long term unless onychomycosis is also eliminated.
How is onychomycosis treated? Unlike tinea pedis alone, which can be treated with topicals, onychomycosis requires systemic antifungal medications. The most effective treatment is oral terbinafine. Second line therapy of pulse dosed itraconazole is less effective alternative. If a patient has both tinea pedis and onychomycosis, it is important to address the toenail fungus. Tinea pedis cannot be eradicated unless the toenails are cured, because the nails will cause reinfection back to the skin

31. Tinea versicolor (TV)
Due to an overgrowth of a yeast (Pityrosporum ovale), which thrives on lipids, such as sebum
Tinea versicolor (TV) usually presents as hypo or hyperpigmented macules with very fine scale on upper chest, upper back, shoulders
Hypopigmentation is due to dicarboxylic acid produced by the yeast, which inhibits melanin formation
The last skin infection for review today is tinea versicolor. Unlike the other tinea infections, tinea versicolor is thought to be due to an overgrowth of yeast on the skin, pitoryosporum ovale. P ovale is present on the majority of individuals. Tinea versicolor typically presents as hypo or hyperpigmented annular macules with fine scale typically found on the upper trunk (both back and chest). The hypopigmentation is due to dicarboxylic acids produced by the yeast, which inhibits melanin formation. This hypopigmentation can persist for months even after treatment.

32. Physical exam: T. versicolor
In this clinical photo, one can see the annular patches, some with mild scale on the upper trunk

33. Physical exam: T. versicolor
This shows more of the hypopigmentation that can occur s well as the fine overlying scale.

34. Tinea versicolor: Diagnosis and Treatment
Diagnosis made on physical exam and KOH scraping with characteristic “spaghetti and meatballs” appearance of hyphae and spores
Treat with antifungal shampoos, such as selenium sulfide or ketoconazole, and/or with single doses of oral ketoconazole
A KOH skin scraping can show blunt ended hyphae with spores, often nicknamed “spaghetti and meatballs”. Treatment is aimed at dealing with the overgrowth of yeast using anti-yeast agents, such as a topical shampoo with selenium sulfide or ketoconazole. If severe or widespread, pts can be treated with a single dose of oral ketoconazole, repeated in a week for full effectiveness.

35. Tinea versicolor: KOH scraping
This slide illustrates the spaghetti and meatballs combination of spores (which are the meatballs) and the hyphae (which is the spaghetti part)

36. Summary: Dermatophyte Infections
Very common superficial fungal infections
Often named for the body location targeted
Tinea capitis, corporis, cruris, pedis
Most common dermatophytes
T. tonsurans, rubrum, mentagrophytes and M. canis
Physical exam often characteristic, can confirm with KOH scraping and fungal culture
Treatment with topical/oral antifungals
Today I reviewed the more common superficial fungal infections. These dermatophyte infections can present in a variety of different ways, often characterized by the body location effected. The physical exam findings along with KOH scrapings help determine the diagnosis, with treatment mainly centered upon topical and/or oral antifungals.

37. Cutaneous Fungal Infections Quiz

38. Thank you for completing this module
I hope that I was able to teach the subject clearly.
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