Adult Cutaneous Fungal Infections

1. Adult Cutaneous Fungal Infections Medical Student Core Curriculum in Dermatology Last updated May 23, 2011

2. Module Instructions • The following module contains a number of blue, underlined terms which are hyperlinked to the dermatology glossary, an illustrated interactive guide to clinical dermatology and dermatopathology. • We encourage the learner to read all the hyperlinked information.

3. Goals and Objectives • The purpose of this module is to help medical students develop a clinical approach to the evaluation and initial management of patients presenting with cutaneous fungal infections. • By completing this module, the learner will be able to: • Identify and describe the morphologies of superficial fungal infections • Describe the correct procedure for performing a KOH examination and interpreting the results • Recognize the use and limitations of KOH examination and fungal cultures to diagnose fungal infections • Recommend an initial treatment plan for an adult with tinea pedis, tinea versicolor, candidal intertrigo, and seborrheic dermatitis

4. Superficial Fungal Infections: The Basics • Dermatophytoses are estimated to affect 20-25% of people worldwide, making them one of the most common infections. • Superficial cutaneous fungal infections are limited to the epidermis, as opposed to systemic fungal infections (e.g. endemic mycoses and opportunistic infections). • Three groups of cutaneous fungi cause superficial infections: dermatophytes, Malassezia spp., and Candida spp. • Dermatophytes (which include Trichophyton spp., Microsporum spp., and Epidermophyton spp.) infect keratinized tissues: the stratum corneum (outermost epidermal layer), the nail or the hair. • The term tinea is used for dermatophytoses and is modified according to the anatomic site of infection, e.g. tinea pedis

5. Case One Mr. Eugene Brown

6. Case One: History • HPI: Eugene Brown is a 62-year-old healthy man who presents to his primary care physician with a one-year history of itching and burning of his feet. • PMH: no chronic illnesses or prior hospitalizations • Medications: none • Allergies: no known allergies • Family history: noncontributory • Social history: lives with wife, works as a banker • Health-related behaviors: reports no alcohol, tobacco or drug use • ROS: increased nocturia, otherwise negative

7. Case One: Skin Exam • How would you describe these exam findings?

8. Case One: Skin Exam • Erythema and scaling are present on the plantar surface and between the toes

9. Case One, Question 1 • Which of the following is Mr. Brown’s most likely diagnosis? • Atopic dermatitis • Candidal intertrigo • Onychomycosis • Psoriasis • Tinea pedis 9

10. Case One, Question 1 Answer: e • Which of the following is Mr. Brown’s most likely diagnosis? • Atopic dermatitis(Characterized by red patches and plaques ± scale. Lichenification may also result) • Candida intertrigo (Erythematous, eroded areas with satellite papules. Less likely location) • Onychomycosis(Fungal infection of the nail) • Psoriasis(The interdigital and plantar surfaces of the toes are unusual locations for psoriasis. Would expect a well-demarcated plaque with a thick silvery scale) • Tinea Pedis

11. Tinea Pedis: The Basics • Tinea pedis (“athlete’s foot”) is the most common fungal infection seen in developed countries, and is most commonly caused by the fungus Trichophyton rubrum • Shoes provide an ideal environment for fungus to grow due to moisture • Public showers, gyms, and swimming pools are common sources of infection • It is difficult to permanently cure and may often recur • There are three clinical patterns of infection: interdigital, moccasin, and vesiculobullous type

12. Tinea Pedis: Interdigital Type Most common, presents with scaling and redness between the toes and may have associated maceration.

13. Tinea Pedis: Moccasin Type Also known as chronic hyperkeratotic type. Sharply marginated scale, distributed along lateral borders of feet, heels, and soles. At times, vesicles and erythema are present at the margins. Often associated with onychomycosis (nail fungal infection).

14. Tinea Pedis: Moccasin Type Moccasin type may present as “one hand, two feet” syndrome. Affected hand shows unilateral fine scaling, particularly in the creases (see below), and nails are often involved.

15. Tinea Pedis: Vesiculobullous Type Grouped, 2-3 mm vesicles or bullae are seen, often on the arch or instep. They may be itchy or painful. Vesiculobullous type tinea pedis represents a delayed hypersensitivity immune response to a dermatophyte.

16. Back to Case One Eugene Brown

17. Case One, Question 2 • Which of the following is the most appropriate next step in diagnosis? • Begin empiric treatment with antifungals. • KOH exam • Skin biopsy • Wood’s light

18. Case One, Question 2 Answer: b • Which of the following is the most appropriate next step in diagnosis? • Begin empiric treatment with antifungals(First need a diagnosis. There are many scaly eruptions that can occur on the foot) • KOH exam • Skin biopsy (This is too invasive when a simpler test is available) • Wood’s light(Organisms will not fluoresce on wood’s light)

19. Case One: KOH Exam What are the diagnostic features in this KOH exam? Magnification 40x

20. Case One: KOH Exam What are the diagnostic features in this KOH exam? • Parallel walls throughoutthe entire length • Septated and branching hyphae Magnification 40x

21. KOH Exam: Basic Facts • KOH microscopy is the easiest and most cost effective method used to diagnose fungal infections of the hair, skin, and nail. • Proper technique requires training. • Sensitivity is dependent on the operator’s experience. • KOH dissolves keratinocytes to allow easy viewing of hyphae. • Heat is used to accelerate this reaction.

22. The KOH Exam Procedure Clean and moisten skin with alcohol swab Collect scale with #15 scalpel blade Put scale on center of glass slide Add drop of KOH and coverslip; heat slide gently with flame to adequately dissolve keratin Microscopy: scan at 10X to locate hyphae; then study in detail at 40X if needed Click here to watch the video Make sure to turn on your computer volume (video length 8min 41sec)

23. Case One, Question 3 • Which of the following are possible pitfalls of KOH prep? • False negative KOH due to prior partial treatment with antifungals • Misidentification of clothing fibers or lint as hyphae • Possibility of mistaking lipid or cell membranes for hyphae • All of the above are limitations

24. Case One, Question 3 Answer: d • Which of the following are possible pitfalls of KOH prep? • False negative KOH due to prior partial treatment with antifungals • Misidentification of clothing fibers or lint as hyphae (clothing fibers or lint are tapered, while hyphae have parallel walls throughout) • Possibility of mistaking lipid or cell membranes for hyphae (hyphae have parallel walls throughout and tend to be longer) • All of the above are limitations

25. Treatment of Tinea Pedis: Hygiene • For all types of tinea pedis, hygieneandtopical antifungals areeffective first-line therapies • Hygiene: • Dry the area after bathing • Change socks daily and alternate shoes worn • Consider wearing open shoes such as sandals • Use foot powder (available over the counter) to keep feet dry

26. Topical Antifungals • There are several classes of topical antifungal medications • Some classes are fungistatic (stop fungi from growing), others are fungicidal (they kill fungi) • Not all conditions are treatable with topical antifungals (specifically, hair infections and nail infections do not respond to topical treatment and require systemic treatment)

27. Treatment of Tinea Pedis: Topical • Topical antifungals: apply until tinea shows resolution, then continue treatment for a minimum of two weeks • Imidazoles: Fungistatic • Examples: clotrimazole, miconazole, sulconazole, oxiconazole, ketoconazole (least activity against dermatophytes) • Allylamines: Fungicidal • Examples: terbinafine, butenafine, naftifine • Ciclopirox: Fungicidal and fungistatic • Example: Ciclopirox olamine

28. Treatment of Tinea Pedis By Type • Interdigital: • Topical imidazoles, ciclopirox olamine, and allylamines • Plantar Moccasin/Chronic Hyperkeratotic: • Topical allylamines and imidazoles • Keratolytics are also useful: e.g. salicylic acid, benzoic acid (Whitfield’s ointment)*, urea, and lactic acid • Vesiculobullous: • Compresses in conjunction with antifungal agents • May require an oral agent such as terbinafine or itraconazole • * Whitfield’s ointment is a combination of salicylic and benzoic acid. In US can be bought through online pharmacies or compounded.

29. Case One, Question 5 • Which of the following are common complications of tinea pedis? You may choose more than one answer. • Deep vein thrombosis • Furunculosis of the lower leg • Lower leg cellulitis • Peripheral neuropathy • Tinea corporis

30. Case One, Question 5 Answer: c & e Which of the following are common complications of tinea pedis? Deep vein thrombosis Furunculosis of the lower leg Lower leg cellulitis (the most common risk factor for lower leg cellulitis in immunocompetent non-diabetics is tinea pedis, which creates a portal of entry for bacteria) Peripheral neuropathy Tinea corporis (from autoinoculation) 30

31. Onychomycosis • Another complication of tinea pedis is onychomycosis, a chronic fungal infection of the nailbed that tends to spread to other nails. • Responds very poorly to topical antifungals • First line treatments are oral terbinafine or itraconazole

32. Onychomycosis • Identification of fungus in the affected nail (at minimum a positive KOH prep or nail biopsy) is necessary before treatment, for several reasons: • May mimic other conditions (e.g. psoriasis, lichen planus) • Treatment is expensive, of long duration, and with potential side effects • Oral antifungals also have drug-drug interactions

33. Case Two Mr. Daniel Green

34. Case Two: History • HPI: Daniel Green is a healthy 18-year-old who presents with a lesion on his right leg that has been present for 2 weeks. The lesion is itchy and is growing in size. • PMH: no major illnesses or hospitalizations • Medications: none • Allergies: none • Family history: noncontributory • Social history: Lives with his parents and sister. The family adopted a puppy 3 months ago. No history of recent travel. • Health-related behaviors: no tobacco, alcohol or drug use.

35. Case Two: Skin Exam • How would you describe these exam findings?

36. Case Two: Skin Exam • This is a sharply marginated, erythematous annular lesion with central clearing and raised papulovesicular border with scaling.

37. Case Two, Question 1 • Which of the following is the most appropriate next step in diagnosis? • Biopsy • KOH exam • Wood’s light exam • All of the above

38. Case Two, Question 1 Answer: b • Which of the following is the most appropriate next step in diagnosis? • Biopsy • KOH exam • Wood’s light exam • All of the above

39. Case Two, Question 2 • Which of the following is the most likely diagnosis? • Atopic dermatitis • Psoriasis • Seborrheic dermatitis • Tinea corporis • Tinea cruris

40. Case Two, Question 2 Answer: d • Which of the following is the most likely diagnosis? • Atopic dermatitis(Poorly defined erythematous patches without central clearing) • Psoriasis(Well-demarcated erythematous plaques with silvery scale) • Seborrheic dermatitis(Inflammatory reaction to yeast typically affecting face, chest, and/or scalp, often with scaling) • Tinea corporis • Tineacruris(Dermatophyte infection in the groin)

41. Tinea Corporis • Tinea corporis, “ringworm”, refers to dermatophytosis of the skin, usually affecting the trunk and limbs • Affects all age groups • Most prominent symptom is itching • Asymmetric distribution • The margin of the lesion is the most active; central area tends to heal • Scrapings should be taken from the red scaly margin for KOH exam • A variant of this is tinea cruris or “jock itch”, which has a similar presentation but appears in the groin

42. Tinea Corporis • Annular lesion with central clearing is typical of tinea corporis

43. Why Perform A Fungal Culture? • Cultures identify the specific species of fungi causing the infection • As opposed to tinea pedis, tinea corporis is caused by different fungal species with different environmental sources • Animals (cats/dogs), tinea capitis, tinea pedis • Using a fungal culture to identify the species will help identify the source and guide treatment • Even if the KOH prep is negative, a culture may be positive

44. Tinea Corporis: Treatment • Begin with topical treatment • Topical antifungals are applied until tinea shows resolution, then continue treatment for a minimum of two weeks • Imidazoles (fungistatic) • Allylamines (fungicidal) • Ciclopirox (fungicidal and fungistatic) • Oral antifungals are indicated in the following situations: • If there is a poor response to topical agents • If an animal is the source of infection • If eruptions involve a large surface area

45. Ms. Anna Jones Case Three

46. Case Three: History • HPI: Ms. Jones is a 27-year-old woman who presents with mild itchiness of her back which began mid summer. She is also concerned about areas on her back that do not tan. • PMH: asthma • Medications: occasional multivitamin • Allergies: no known drug allergies • Social history: spends her summer months in Florida. Is an avid runner. • Health-related behaviors: occasional glass of wine 1-2 times per month, no tobacco or drug use • ROS: negative

47. Case Three: Skin Exam • How would you describe these exam findings?

48. Case Three: Skin Exam • Well-demarcated, pink and tan, macules and patches, across the back.

49. Case Three, Question 1 • Which of the following is the most likely diagnosis? • Pityriasis alba • Seborrheic dermatitis • Tinea corporis • Tinea versicolor • Vitiligo

50. Case Three, Question 1 Answer: d • Which of the following is the most likely diagnosis? • Pityriasis alba(noninfectious, asymptomatic poorly-defined areas of hypopigmentation; self-limited) • Seborrheic dermatitis(abnormal immune response to normal skin yeast causing scaling and crusting) • Tinea corporis(fungal skin infection, presents as erythematous annular lesions with central clearing) • Tinea versicolor • Vitiligo(autoimmune loss/dysfunction of melanocytes causing areas of complete depigmentation)