Roles & Responsibilities of the Advanced Nurse Practitioners

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Chapter 12:

Fungal Infections of the Skin

Tinea

Tinea versicolor

Candidiasis

Types of Tinea Infections

Tinea capitis: head

Tinea corporis: body

Tinea pedis: foot

Tinea manus: hand

Tinea unguium (onychomycosis): nails

Tinea cruris: groin

Factors Predisposing People to Fungal Infections

Warm, moist, occluded environments

Family history

Compromised immune system

Five Species of Fungus Causing Most Infections

Trichophyton rubrum

Trichophyton tonsurans

Trichophyton mentagrophytes

Microsporum canis

Epidermophyton floccosum

Diagnostic Criteria for Fungal Infections

Symptoms

Pruritus, burning, and stinging of the scalp or skin, possible erythema and vesicles with inflammatory dermal reactions.

Diagnostic tests

Microscopic evaluation of the stratum corneum with 10% potassium hydroxide (KOH) preparation

Fungal culture

Wood lamp (identifies only Microsporum)

Tinea Capitis Presentation

Inflamed, scaly, alopecic patches, especially in infants

Diffuse scaling with multiple round areas with alopecia secondary to broken hair shafts, leaving residual black stumps

“Gray patch” type with round, scaly plaques of alopecia in which the hair shaft is broken off close to the surface

Tender, pustular nodules

Tinea Corporis

Called “ringworm” when it affects the face, limbs, or trunk but not the groin, hands, or feet

Presentation: ring-shaped lesion with well-demarcated margins, central clearing, and a scaly, erythematous border

Causes: contact with infected animals, human-to-human transmission, and from infected mats in wrestling

Organisms responsible: M. canis, T. rubrum, and T. mentagrophytes

Tinea Cruris

Often referred to a “jock itch.”

A fungal infection of the groin and inguinal folds, tinea cruris spares the scrotum.

Causes are T. rubrum or E. floccosum.

Symptoms: lesions that are large, erythematous, and macular, with a central clearing; a hallmark is pruritus or a burning sensation.

Often fungal infection of the feet is present.

Three Types of Tinea Pedis

Interdigital: scaling, maceration, and fissures between the toes

Plantar: diffuse scaling of the soles, usually on the entire plantar surface

Acute vesicular: vesicles and bullae on the sole of the foot, the great toe, and the instep

Characteristics of Tinea Manus

Dermatophyte infection of the hand

Always associated with tinea pedis and usually unilateral

Lesions marked by mild, diffuse scaling of palmar skin

Vesicles may be grouped on the palms or fingernails involved

Tinea Unguium

Fungal infection of the nail; typically the toenails.

Nails become thick and scaly with subungual debris.

Onycholysis (nail separation from bed) may occur.

Under the nail, a hyperkeratotic substance accumulates that lifts the nail up.

Organisms causing onychomycosis: dermatophytes, E. floccosum, T. rubrum, T. mentagrophytes, Candida albicans, Aspergillus, Fusarium, and Scopulariopsis.

Question

Upon physical examination, a practitioner notes a ring-like lesion with a scaly, erythematous border on the trunk of a child. What fungal infection would the practitioner suspect?

Tinea capitis

Tinea corporis

Tinea cruris

Tinea pedis

Answer

B. Tinea corporis

Rationale: Tinea corporis is called “ringworm” when it affects the face, limbs, or trunk. The typical presentation of tinea corporis is a ring-shaped lesion with well-demarcated margins, central clearing, and a scaly, erythematous border. Tinea capitis affects the scalp, tinea cruris affects the groin, and tinea pedis affects the feet.

Initiating Drug Therapy for Fungal Infections

Prevention: applying powder containing miconazole (Monistat) or tolnaftate (Tinactin) to areas prone to fungal infections after bathing and blow drying on low temperature

Goals of drug therapy: directed against the offending fungus and site of infection; may be topical or systemic depending on location of lesions

Topical Azole Antifungals

Action: work by pairing the synthesis of ergosterol, the main sterol of fungal cell membranes, allowing for increased permeability and leakage of cellular components, resulting in cell death.

Uses: effective against tinea corporis, tinea cruris, and tinea pedis as well as cutaneous candidiasis.

Dosage: applied once or twice a day for 2 to 4 weeks. Therapy should continue for 1 week after the lesions clear.

Topical Allylamine Antifungals

Action: effective against dermatophyte infections but have limited effectiveness against yeast

Dosage: shorter treatment period with less likelihood of relapse; applied twice daily

Adverse events: burning and irritation

Griseofulvin

Action: deposits in keratin precursor cells increasing new keratin resistance to fungal invasion.

Adverse events: nausea, vomiting, diarrhea, headache, or photosensitivity.

Interactions: increases levels of warfarin (Coumadin) and decreases levels of barbiturates and cyclosporine (Sandimmune). It may decrease the efficacy of oral contraceptives and may cause a serious and unpleasant reaction with alcohol.

Systemic Allylamine Antifungals

Action: inhibits squalene epoxidase, a key enzyme in fungal biosynthesis, causing a deficiency of ergosterol causing fungal cell death

Dosage: fingernail onychomycosis: 250 mg/d for 6 weeks; toenail onychomycosis: 250 mg/d for 12 weeks

Adverse events: diarrhea, dyspepsia, rash, increase in liver enzymes, and headache

Interactions: potentiated by cimetidine (Tagamet) and antagonized by rifampin (Rifadin)

Systemic Azole Antifungals

Action: inhibit cytochrome P-450 (CYP) enzymes and fungal 14-a-demethylase, inhibiting synthesis of ergosterol. Systemic therapy is required for tinea capitis and tinea unguium.

Dosage: dosage of itraconazole is 200 mg once daily for 12 weeks for toenail infection. For fingernail infection, the dose is 200 mg twice daily for 1 week, then 3 weeks off, and repeat dosing with 200 mg twice daily for 1 week.

Question

For which fungal infection would the practitioner use as first-line therapy a systemic fungicide?

Tinea capitis

Tinea corporis

Tinea pedia

Tinea cruris

Answer

A. Tinea capitis

Rationale: Topical agents work well for most tineas but not for tinea capitis and tinea unguium. Topical therapy is recommended for cases of tinea corporis, pedis, cruris, or manus when the infection affects a limited area.

Selecting the Appropriate Agent for Tinea

Tinea capitis

First line: griseofulvin (Grifulvin V) minimum 8 weeks

Second line: terbinafine (Lamisil) or itraconazole (Sporanox) 4 weeks

Tinea corporis, tinea cruris, tinea pedia

First line: topical azole antifungals for 2 to 4 weeks (1 week past clinical cure), 2 weeks even after rash is gone

Second line: systemic therapy: terbinafine (Lamisil) or fluconazole (Diflucan)

Selecting the Appropriate Agent for Tinea (cont.)

Onychomycosis

First line: itraconazole (Sporanox) or terbinafine (Lamisil) 12 weeks with food; not recommended for children

Tinea versicolor

First line: selenium sulfide solution 1% or 2.5% topical azole cream or spray for localized lesions

Second line: itraconazole (Sporanox)

Question

A clinician treated a patient who has tinea versicolor with selenium sulfide solution without success. What is the second line of therapy for this patient?

Topical azole

Terbinafine (Lamisil)

Fluconazole (Diflucan)

Itraconazole (Sporanox)

Answer

D. Itraconazole (Sporanox)

Rationale: After trying selenium sulfide solution 1% or 2.5% topical azole cream or spray, the second line of therapy for tinea versicolor is itraconazole (Sporanox).

Patient Education for Tinea

Teach hygiene and ways to avoid transferring fungal infection to others.

Complete the full course of treatment and do not stop treatment when symptoms subside.

Inform parents and other caregivers that children can attend school while being treated.

Dry areas susceptible to fungus with a hair dryer after bathing.

Use antifungal powder and sprays for prophylaxis.

Tinea Versicolor (Pityriasis Versicolor)

An opportunistic superficial yeast infection

Causes: overgrowth of the hyphal form of Pityrosporum ovale; occurs mostly in subtropical and tropical areas

Action: an enzyme oxidizes fatty acids in the skin surface lipids, forming dicarboxylic acids, which inhibit tyrosinase in epidermal melanocytes and cause hypomelanosis

Diagnostic criteria: well-defined skin lesions, round or oval macules with an overlay of scales forming on the trunk, upper arms, and neck with mild itching; confirmed by positive KOH test

Candidiasis

Superficial fungal infection of the skin and mucous membranes.

Causes: C. albicans occurs on moist cutaneous sites in people with infection or diabetes, or using systemic and topical corticosteroids, and with immunosuppression.

Action: C. albicans invades the epidermis when warm, moist conditions prevail.

Diagnostic criteria: red, moist papules, or pustules found in the axillae, inframammary areas, groin, and between the fingers and toes.

Order of Treatment for Candidiasis

First line: cool soaks with Burow solution, topical azole for 10 days, oral nystatin

Second line: itraconazole (Sporanox) or fluconazole (Diflucan)

Complementary and Alternative Medicine

Apple cider vinegar

Palin yogurt

Tea tree oil

Tea

Summary

Fungi live in the dead, horny outer layer of the skin.

The organisms penetrate only the stratum corneum—the surface layer of the skin.

Fungi infect the skin, hair, and nails and cause tinea, tinea versicolor, and candidiasis.

An important role of the practitioner is to teach the patient about hygiene and ways to avoid transferring fungal infection to others.