Skin Fungal Infections. Dr. Hani Masaadeh MD, PhD

Transcription

1 Skin Fungal Infections Dr. Hani Masaadeh MD, PhD

2 Cutaneous Fungal Infections odermatophytosis - "ringworm" disease of the nails, hair, and/or stratum corneum of the skin caused by fungi called dermatophytes. odermatomycosis - more general name for any skin disease caused by a fungus.

3 Clinical manifestations of ringworm infections are called different names on basis of location of infection sites tinea capitis - ringworm infection of the head, scalp, eyebrows, eyelashes tinea favosa - ringworm infection of the scalp (crusty hair) tinea corporis - ringworm infection of the body (smooth skin) tinea cruris - ringworm infection of the groin (jock itch) tinea unguium - ringworm infection of the nails tinea barbae - ringworm infection of the beard tinea manuum - ringworm infection of the hand tinea pedis - ringworm infection of the foot (athlete's foot)

4 Diagnosis Note the symptoms. Microscopic examination of slides of skin scrapings, nail scrapings, and hair. Often tissue suspended in 10 % KOH solution to help clear tissue. Slides prepared this way are not permanent. These degrade rapidly due to presence of base. Isolation of the fungus from infected tissue.

5 DERMATOPHYTES Trichophyton violaceum Attacks hair, scalp, skin and nails. Nail infections are persistent. Endothrix (black dot infection of scalp). Very slow growing in culture with a waxy appearance. Colony deep violent in color, purplish pigment diffuses into media. Rarely produces microconidia and macroconidia. Chlamydoconidia are seen in culture.

6 WHAT IS RINGWORM? Ringworm is a common fungal skin infection otherwise known as tinea. Ringworm most commonly affects the skin on the body (tinea corporis), the scalp (tinea capitis), the feet (tinea pedis, or athlete's foot), or the groin (tinea cruris, or jock itch).

7 RINGWORM OF THE BODY (TINEA CORPORIS) There are several types of ringworm (tinea) that can affect different parts of the body. When fungus affects the skin of the body, it often produces itchy, red, raised, scaly patches that may blister and ooze. The patches often have sharply defined edges

8 RINGWORM OF THE SCALP (TINEA CAPITIS) Ringworm of the scalp commonly affects children in late childhood or adolescence. This condition may spread in schools. Tinea capitis often appears as patchy, scaling bald spots on the scalp

9 RINGWORM OF THE FOOT (TINEA PEDIS) Tinea pedis is an extremely common skin disorder, also known as athlete's foot. This fungal infection may cause scaling and inflammation in the toe webs, especially the one between the fourth and fifth toes. Other symptoms include itching, burning, redness, and stinging on the soles of the feet

10 RINGWORM OF THE HAND (TINEA MANUS) Ringworm may involve the hands, particularly the palms and the spaces between the fingers. It typically causes thickening (hyperkeratosis) of these areas, often on only one hand.

11 RINGWORM OF THE NAILS (TINEA UNGUIUM) Ringworm is the most common fungal infection of the nails, also called onychomycosis. It can make fingernails look white, thick, opaque, and brittle, but more often toenails look yellow, thick, and brittle. Artificial nails increase the risk for tinea unguium as emery boards can carry infection

12 CATCHING RINGWORM FROM PETS Ringworm is an example of a zoonotic disease (transmitted from animals to humans). Cats are among the most commonly affected animals. If a cat has ringworm, a person in the house often gets the infection. Dogs, cows, goats, pigs, and horses can also spread ringworm to humans.

13 Diagnostic Tests KOH Preparations Skin Two slides or slide and #15 blade. Scrape border of lesion. Apply 1-2 drops of KOH and heat gently Examine at 10x and 40x Focus back and forth through depth of field. Look for hyphae Clear, Green Cross cell interfaces Branch, constant diameter. Chlorazol black, Parkers ink can help.

14 Diagnostic Tests KOH Preparations Nails Thin clipping, shaving or scraping Let dissolve in KOH for 6-24 hours. Can be difficult to visualize. Culture often required. Hair Directly examined without KOH. Apply KOH and heat hair until macerated Look for spores.!

15 Diagnostic Tests Fungal Cultures DTM (Dermatophyte Test Medium) Yellow to red is (+). Nickerson s Media Yeast Black growth is (+) Sabouraud s Media Molds

16 Diagnostic Tests Fungal Culture Sample Collection Scrape with blade or rub with cotton Q-tip. Nail clipping or curette. Implant in media. Cap Loosely, Fungi are aerobic Read at 2 weeks and 4 weeks.

17 Tinea Capitis

18 Tinea Capitis Children most common cases.

19 Tinea Capitis Presentations of Tinea Capitis 1. Non-inflammatory black dot type 2. Seborrheic type 3. Pustular 4. Inflammatory (Kerion)

20 Tinea Capitis Black Dot Type Large Areas of Alopecia without inflammation Mild scaling Occipital adenopathy Black dot hairs. At first glance may look like Alopecia areata

21 Tinea Capitis

22 Tinea Capitis Seborrheic type Common resembles dandruff Close exam for broken hairs, black dots Adenopathy Frequently negative KOH (70%) Culture often necessary for DX

23 Tinea Capitis - Kerion

24 Tinea Capitis Diagnosis History Close contacts, pets, duration. Morphology of lesion Broken hairs, black dots, localized. Woods Lamp Blue green. Hair Shaft Exam Endo/Exothrix Culture Plucked Hair shafts, Q-tip or tooth brush.

25 Tinea Capitis - Endothrix

26 Tinea Capitis - Exothrix KOH and Quick Ink M. Canis

27 General Morphology Tinea Pedis

28 Tinea Pedis

29 Tinea Pedis Groups: M > F. Young and middle aged. Patient is susceptible to reoccurrence Onychomycosis and tinea pedis associated. Differential: Eczema, contact dermatitis Psoriasis. Erythrasma and Candida (esp in web spaces.) Pitted keratolysis

30 Tinea Pedis Diagnosis PE/History onychomycosis, contacts, med cond. KOH exam Thick scale, no leading edge Woods Light - Helps to differentiate from erythrasma Culture Remember: hand eczema may be a dermatophyte infection of hands or id reaction from tinea at another location.

31 Tinea Pedis: Treatment Dry Feet Alternate shoes, Absorbent powders, Change socks Scale my be reduced with keratolytic Topicals and/or Systemics. Topical: naftine, lamisil, mentax may be more effective than azoles. Steroids if inflamed. Systemic allyamines or azoles Treat secondary bacterial infections. Steroids for severe inflammation and ID.

32 Candidaisis of nail Paronychia

33 Psoriasis Middle of nail, oils spots, pitting.

34 Psoriasis

35 Lichen Planus

36 Pseudomonas of nail

37 General Morphology Tinea Corporis Papulosquamous Erythematous Annular Scaling Crusting Ringworm

38 Candidiasis Candida Albicans Normal Flora Occurs in moist areas especially where skin touches. Presentation: primary lesion is a red pustule.

39 Candidiasis Immunosuppression of any type (disease, steroids), D.M., Antibiotics or receptive environments predispose. Diagnosis: History of predisposing factors and/or classic appearance of lesions at typical locations. Red and glistening in intertriginous area esp in predisposed individual think candida.

40 Candidiasis

41 Candidiasis

42 Difficult to be sure in Web spaces.

43 Candidiasis Differential: 1. Erythrasma likes skin creases 2. Eczema may look like pustular candida 3. Bacterial folliculitis as above 4. Psoriasis gluteal cleft 5. Tinea same locations

44 Candidiasis KOH for pseudohyphae and spores May be impossible to tell visually from tinea. Woods Light Culture. Nickersons (+) Remember yeast part of normal flora. Add up the evidence

45 Candidiasis

46 Treatment of Candidiasis Keep dry Z-sorb powder, cotton ball between toes. Topical azoles. Occasionally co-administration of a weak topical steroid may be helpful. Diaper rash Angular chelitis. Treat co-existent bacterial infection if present.

47 THE END