Fungal Infections of the Skin

Question 1

Where do fungi live?

Answer 1

Dead, horny outer layer, penetrate only the stratum corneum aka surface layer of skin. Fungi infect the skin, hair, and nails.

Fungus can be found on humans, animals, and in the soil.

Question 2

What diseases are caused by fungi?

Answer 2

tinea, tinea versicolor, and candidiasis (yeast infection)

Question 3

Causes of fungal infection

Answer 3

warm, moist, occluded environments

family history

compromised immune system

Question 4

Dermatophytes

Answer 4

Grows only on or within keratinized structures.

Question 5

tinea capitis

Answer 5

fungal infection of the scalp

age 3 - 9 mostly

disproportionally African American

15% infected has cross-infection with tinea corporis

very contagious

SX impetigo-like lesions with crusting and redness, inflamed, scaly, gray patch type plaques alopecia, tender and pustular nodules.

in severe cases and painful in a child, prednisone (Deltasone) 1 mg/kg/d for 3 to 4 days given to child pt

Question 6

tinea corporis

Answer 6

“Ringworm” it affects the face, limbs, and trunk,
but NOT the groin, hands, or feet

SX ring-shaped lesion with well-demarcated margins, central clearing, scaly, erythematous border

commonly transmitted from infected mats in wresting or martial arts

Question 7

tinea cruris

Answer 7

“Jock itch”, affects groin and inguinal folds, but not the scrotum;

SX large lesions, erythematous, well-demarcated and peripherally spreading, macular and with central clearing

hallmark sx pruritus or burning sensation

often accompanied by fungal infection of the feet

Question 8

tinea pedis

Answer 8

“Athlete’s foot”, affects web spaces between toes, sometimes toes or instep

SX scaling, itching, denudation, sodden maceration, vesicles, thickness and cracking of epidermis on the sole, heel, side of foot.

Question 9

tinea unguium

Answer 9

Onychomycosis; fungal infection of the nail;

usually asymptomatic but is portal of entry for more serious bacterial infection;

onycholysis - separation of the nail from the nail bed;

scaly with subungual debris;

when untreated, nail thickens and turns yellowish brown.

Question 10

How to prevent fungal infections

Answer 10

Apply powder containing miconazle (Monistat) or tolnaftate (Tinactin) after bathing, dry completely with hair dryer on low heat.

Question 11

Drug therapy for fungal infections

Answer 11

Topical TX for most fungal infections except tinea capitis and tinea unguium.

Question 12

Types of antifungals

Answer 12

topical azoles

topical allylamine

griseofulvin

systemic azoles

systemic allylamine

Question 13

Topical azole antifungals

Answer 13

TX tinea corporis, tinea cruris, tinea pedis, cutaneous candidiasis

RX ketoconazole (Nizoral) - not for sulfite sensitive pt, clotrimazole (Lotrimin), miconazole (Monistat, Micatin)

applied BID for 2 to 4 weeks, and continued for 1 more week after lesions clear

CX pregnancy or lactation

caution in pt with hepatocellular failure (liver failure)

AX stinging, irritation, pruritis, erythema

Question 14

Topical allylamine antifungals

Answer 14

TX dermatophyte infections, NOT yeast (tinea versicolor and candidiasis)

RX terbinafine (Lamisil) - CX sun exposure or tanning beds, children, occlusive dressing, mucous membranes; and naftifine (Tinactin) - CX children < 2 yo (but NOT tolnaftate)

AX burning, irritation, dry skin, skin exfoliation

Question 15

Order of tx for tinea corporis, tinea cruris, and tinea pedis

Answer 15

1st line
topical azole antifungals 2 to 4 weeks including an additional 2 weeks after rash is gone

2nd line
systematic therapy (PO) usually with terbinafine or fluconazle.

Question 16

griseofulvin

Answer 16

Systemic (PO) antifungal

CX pregnancy, prophyria, hepatic failure

AX HA, n/v/d, photosensitivity, alcohol use

RX
aggravate lupus
increase warfarin levels
decrease barbiturates and cyclosporine levels
decrease oral contraceptive effectiveness
bad reaction with alcohol

Question 17

Order of tx for tinea capitis

Answer 17

1st line
griseofulvin for 8 weeks

2nd line
terbinafine for 4 weeks

Question 18

Order of tx for tinea unguium (onychomycosis)

Answer 18

1st line
PO itraconazle for 12 weeks

2nd line
terbinafine for 12 weeks

Question 19

Systemic allylamine antifungals

Answer 19

TX tinea unguium

AX diarrhea, dyspepsia, rash, liver failure (check ALT and AST prior TX and at 6 - 8 wks), HA

RX terbinafine (Lamasil)

terbinafine is potentiated by cimetidine (Tagamet) and antagonized by rifampin (Rifadin), check level of cyclosporine if taking both terbinafine and cyclosporine.

Question 20

Systemic azole antifungals

Answer 20

TX tinea capitis, tinea unguium

pulse dosing due to long half-life

CX pregnancy, pt on quinidine

RX fluconazole (Diflucan)

AX GI upset, rash, fatigue, hepatic dysfunction, edema, hypokalemia

fluconazole (Diflucan) level increases when given with hydrochlorothiazide (Hydrodiuril)

systemic azole potentiates hypoglycemic drugs, triazolam (Halcion), midazolam (Versed), and warfarin

avoid taking systemic azole within 2 hours of taking anticholinergics, histamine-2 blockers, and antacids as they inhibit absorption of systemic azoles

Question 21

tinea versicolor - what is it?

Answer 21

opportunistic superficial yeast infection.

Question 22

Characteristics of tinea versicolor

Answer 22

chronic, asymptomatic infection characterized by well-demarcated, scaling patches of varied coloration from whitish to pink, tan, or brown

Question 23

Causes of tinea versicolor

Answer 23

moist skin surfaces

common in physically active people

common in summer months

Question 24

SX of tinea versicolor

Answer 24

round or oval macules

overlay of scales that may group together to form larger patches

found on trunk, upper arms, and neck

mild itching

confirmed by KOH test positive

Question 25

Order of TX for tinea versicolor

Answer 25

1st line
selenium sulfide solution 1% OR
2.5% topical azole cream OR
2.5% topical azole spray

2nd line
PO itraconazole (Sporanox)

Question 26

selenium sulfide

Answer 26

TX tinea versicolor

CX pregnancy, lactation, no eye areas

AX irritation, alopecia

Question 27

Causes of candidiasis

Answer 27

infection

diabetes

use of systemic and topical corticosteroids

immunosuppression

thrives in occluded sites

commonly found in people who immerse their hands in water

Question 28

Order of TX for candidiasis

Answer 28

1st line
cool soaks with Burow solution OR
topical azole OR
oral nystatin (Mycostatin)

2nd line
itraconazle (Sporanox) OR 
fluconazole (Diflucan) OR 
PO itraconazole OR
PO fluconazole

Question 29

CAM for fungal infections

Answer 29

apple cider vinegar PO or applied externally;

plain yogurt (it produces lactic acid keeping fungi growth in check)

tea tree oil (has natural antifungal compounds)

tea (tannins in tea has antibiotic properties) PO or applied externally