Spaghetti meatball appearance is classical for yeast The most common pathogen for tinea capitus used to be microsporoum. It is now T. Tonsauran thus render wood’s light useless
Mostly nursing home patient with no nail care Note the concurrent tinea pedis
Fungal Infection of the Skin
Michael Hohnadel D.O.
Basic diagnostic techniques
– Woods light
Tinea infections with special attention to scalp, feet and
Differentials to consider.
1. What is a Wood’s light useful for ?
2. If I think it might be a fungus but it is KOH negative,
what can be done to prove it ?
3. How do you know the endpoint of therapy when
treating tinea capitis ?
4. How do you know the endpoint of therapy when
treating tinea versicolor ?
5. If a patient has thick ugly nails, what is the chance
that it is classic onychomycosis ?
– 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
Cross cell interfaces
Branch, constant diameter.
– Chlorazol black, Parkers ink can help.
– Thin clipping, shaving or scraping
– Let dissolve in KOH for 6-24 hours.
– Can be difficult to visualize.
– Culture often required.
– Directly examined without KOH.
– Apply KOH and heat hair until macerated
– Look for spores.
Be Persistent !
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.
– Tinea Capitis
Blue green florescent with M. Canis.
Not useful for Trichophyton (Most Common)
– Other Areas:
Useful to diagnose as erythrasma (coral red/pink).
Tinea versicolor may be pale white yellow.
Less helpful if patient recently bathed.
PAS stain of skin or nail clipping.
• Children most common cases.
• Most Common Organisms:
• T. Tonsurans - acounts for 90% in U.S.
• M. Canis - seen in children with infected animals.
•Adults not infected.
• M. Audouinii - grey, broken shaft tinea
Presentations of Tinea Capitis
1. Non-inflammatory ‘black dot’ type
2. Seborrheic type
4. Inflammatory (Kerion)
Black Dot Type
Large Areas of Alopecia without
Black dot hairs.
At first glance may look like Alopecia areata
Tinea Capitis - Exothrix
KOH and ‘Quick Ink’
Tinea Capitis Treatment
•Must treat hair follicle
•Topical not effective
•Griseofulvin for children – liquid with good taste.
•Steroids for inflamed lesions like Kerion.
•Treat until no visual evidence, culture (-)… plus 2 weeks
•Average of 6-12 weeks of treatment.
•Examine / treat family in recurrent cases.
Tinea Pedis and
T. Rubrum most common etiology
•Dull erythema with pronounced scale.
•Leading edge of scale not as common.
•Two feet one hand involvement.
•T. Mentagrophytes causes inflammatory
•Vesicles and bullae.
•Groups: M > F. Young and middle aged.
•Patient is susceptible to reoccurrence
•Onychomycosis and tinea pedis associated.
•Eczema, contact dermatitis
•Erythrasma and Candida (esp in web spaces.)
Tinea Pedis Diagnosis
•PE/History – onychomycosis, contacts, med cond.
•KOH exam – Thick scale, no leading edge
•Woods Light - Helps to differentiate from erythrasma
•Remember: ‘hand eczema’ may be a
dermatophyte infection of hands or id reaction
from tinea at another location.
Tinea Pedis: Treatment
•Alternate shoes, Absorbent powders, Change socks
•Scale my be reduced with keratolytic
•SAL acid, Lactic acid, Carmol
•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.
15-20% of those between 40-60 yrs. infected.
No Spontaneous remissions
– Typically begins at distal nail corner
– Thickening and opacification of the nail plate
– Nail bed hyperkeratosis
– Discoloration: white, yellow, brown
– Edge of the nail itself becomes severely eroded.
Some or all nails may be infected
Often accompanying tinea pedis
1. Distal Subungal
2. White superficial
T. Mentagrophytes and molds
Chalky white patches
3. Proximal Subungal
May indicate HIV infection
Normally hands with accompanying paronychia
Diagnosis of Onychomycosis
Try to identify fungi before oral therapy
1. KOH of nail clipping
• May need some time to dissolve nail.
• DTM - dermatophytes
• Sauborauds – Molds
• Nickerson – Yeast
3. Nail clipping for histology and PAS staining if above is
negative and clinical suspicion is high.
Treatment of Onychomycosis.
Debridement of infected area helps penetration / comfort.
• Urea products (ex carmol)
• Can be effective for limited involvement and for
• Penlac (every day for one year)
• Mycocide Nail solution
Treatment of Onychomycosis
•Effective. Relapse rate 15-20 % in one year.
•Lamisil 250mg. 6 weeks/12 weeks.
•Baseline labs and one month.
•CBC (neutropenia), Liver function.
•Itraconazole 200 mg /day. 6 weeks/12 weeks
•Baseline labs and one month. Similar to lamisil.
•Pulse dosing fingernails - (200 mg bid 1 wk q mo.) x 2
•No lab monitoring needed
Treatment of Onychomycosis
Notes on Therapy
• Other Azoles require longer therapy.
• Nails will not appear clear at end of
• Measurements and digital photography
• For you and for patient
Numerous, well-marginated, oval-to-round
macules with a fine white scale when scraped.
Pigmentary alteration uniform in each
– Hypo pigmented
Scattered over the trunk and neck. Seldom the
Pityrosporum orbicularis, M. furfur
– Normal flora of skin
Topicals for limited involvement.
•Selenium Sulfide Shampoos: lather 10
minutes wash off x 7 days.
•Ketoconazole 2% shampoo: 5 minutes 1-3
•Imidazoles topicals to body qd-bid for 2-4
Oral for extensive
•Dosing varies: single dose to 5-10 days of
•Likes gastric ph for absorption.
•Avoid bathing with 12 hours of ingestion.
•Hypopigmentation resolves slowly
•No scale when scraped indicates cure.
•Sunlight helps restore pigment
•Prophylaxis before summer in some patients.
•Q month orals
•Occurs in moist areas especially where skin touches.
•Presentation: primary lesion is a red pustule.
•Most Common: pustules dissect horizontally through the
stratum corneum leaving a red, glistening denuded
surface with long continuous border with satellite lesions.
•May also present as an eruption of multiple pustules
which become erythematous papules between skin folds.
•Immunosuppression of any type (disease,
steroids), D.M., Antibiotics or receptive
•Diagnosis: History of predisposing factors
and/or classic appearance of lesions at typical
•Red and glistening in intertriginous area esp in
predisposed individual think candida.