Onychomycosis Hai Ho, M.D.

Psoriasis Diagnosis? Pitting Nail involvement – 10-50% Usually along with skin lesions, but could be alone Could occur in eczema, fungal infection, and alopecia areta Pitting – abnormal shedding as psoriatic scales Psoriasis

Psoriasis Diagnosis? Pitting Onycholysis Yellow psoriatic debris under the nail causing nail separation Pitting and onycholysis Psoriasis

Diagnosis? Psoriasis Nail matrix involvement leading to nail deformity Plate alteration Psoriasis

Diagnosis? Onycholysis Painless separation of the nail from the nail bed Causes: trauma (long nail in women), hyperthyroidism, prolonged immersion, psoriasis Consider TSH in asymptomatic patient

Traumatic onycholysis Diagnosis? Traumatic onycholysis

Onycholysis May have secondary candida infection Treatment Avoid long nail Tinture containing miconazole under nail Fluconazole for resistant case

Diagnosis? Nail hypertrophy Cause: tight-fitted shoes or chronic trauma Treatment: filing or removing the nail with phenol

Diagnosis? Leukonychia punctata Cause by cuticle manipulation or other mild trauma

Diagnosis? Leukonychia

Diagnosis? Distal splitting nail Analogous to peeling of dry skin Affected 20% of adults Associated with water immersion and use of polish remover Treatment Moisturizer B-complex vitamin biotin (2.5mg/day) for brittle nail

Diagnosis? Pincer nail Due to ?tight shoes Treatment Nail removal Reconstruction of nail unit

Habit-tic onycholysis Diagnosis? Habit-tic onycholysis

Diagnosis? Median dystrophy

Moral of the story Cannot diagnose onychomycosis by visualization alone >50% of fungal-looking nail do not have fungal infection

Common organisms in onychomycosis? Dermatophytes Trichophytum rubum Trichophytum mentagrophytes Contaminants or nonpathogens Aspergillus, Cephalosporium, Fusarium, and Scopulariopsis

Patterns of infection

Distal subungual onychomycosis Most common Fungi invade the hyponychium and grow in the substance of nail plate, causing it to crumble Hyperkeratotic debris causes nail to separate from the bed

Distal subungual onychomycosis Linear channel Infection advance proximally Characteristic feature of fungal infection

White superficial onychomycosis Commonly Trichophyton mentagrophytes Nail - white, soft, powdery

White superficial onychomycosis Nail not thickened not separated from the nail bed

Proximal subungual onychomycosis Commonly Trichophyton Rubrum Invade the substance of nail plate, not the surface Hyperkeratotic debris causes the nail plate to separate from the nail bed

Proximal subungual onychomycosis is associated with what disease? HIV

Candida onychomycosis Almost exclusively in chronic mucocutaneous candidiasis Generally infect all fingernails Linear yellow or brown streaks grow and advance proximally

Candida onychomycosis Yellow areas with hyperkeratosis

Laboratory tests? KOH – improve detection with fluorochrome which binds with chitin in fungal cell wall and fluoresces Culture – gold standard Histological examination by periodic acid-Schiff (PAS) staining – equal to culture

Obtaining specimen Clip the nail for PAS & culture Subungal debris for KOH & culture Fungi reside in the nail plate and cornified cells in the nail bed Hyphae in the nail plate may not be viable, so obtain specimen from nail bed for culture

KOH examination Hard nail plate and debris could be softened overnight with KOH Artifacts – lipid droplet between cells; eliminated by heat which separates cells

Culture Sabouraud's with antibiotics ID the organism Antibiotics suppress bacterial contaminants Medium turn from yellow to red in 7-14 days – alkaline released by dermatophytes turn phenol (pH indicator) red ID the organism Some nondermatophytes, such as Scopulariopsis, Aspergillus, Penicillium, black molds, and yeast, may cause a color change and give a false-positive reaction. The dermatophyte test medium contains the antibiotic cycloheximide and phenol red as a pH indicator. Dermatophytes release alkaline metabolites that turn the medium from yellow to red in 7 to 14 days. Some nondermatophytes, such as Scopulariopsis, Aspergillus, Penicillium, black molds, and yeast, may cause a color change and give a false-positive reaction.

PAS staining In the presence of periodic acid, hydroxyl group of polysaccharide in fungal cell wall oxidized to aldehyde Schiff reacts with aldehyde to stain fungal elements pinkish-red False-negative – sampling error Alan Woodgyer, mycology scientist and Dr Geoff Hogg Fellow of the Royal College of Pathologists of Australasia (First appeared in Medical Observer Weekly 10/10/04)

Treatment

Options Systemic – terbinafine, itraconazole, fluconazole Topical Mechanical

Terbinafine is more effective than itraconazole and fluconazole Oral medications Terbinafine is more effective than itraconazole and fluconazole

Terbinafine vs. intermittent itraconazole Cure rate at 72 weeks Crawford F, et al. Arch Dermatol 2002; 138:811

Terbinafine vs. fluconazole Cure rate at 60 weeks Havu V, et al. Br J Dermatol 2000; 142(1):97.

Ineffective oral regimen Intermittent terbinafine Greseofulvin

Regimen Drug Dosage Fluconazole (Diflucan) One 150-mg dose each week for 9 months Itraconazole (Sporanox) 200 mg/day for 12 weeks for toenails, 6 weeks for fingernails “Pulse dosing”: 400 mg/day for first week of each month Fingernails 2–3 pulses Toenails 3–4 pulses Terbinafine 250 mg/day (12 weeks for toenails, 6 weeks for fingernails)

Adverse effect of terbinafine? Cholestatic hepatitis and blood dyscrasias LFT and CBC prior to and at 6 weeks during treatment Discontinue if AST/ALT >2x normal. Am Fam Physician 2001;63:663-72,677-8

Adverse effect of itraconazole? Hepatitis for continuous but not intermittent regimen LFT prior and at 6 weeks during treatment for continuous, not pulse, regimen Am Fam Physician 2001;63:663-72,677-8

Drug interactions with itraconazole Cytochrome P450 system Arrhythmia with quinidine and primozile Rhabdomyolysis with HMG-CoA reductase inhibitors, such as atorvastatin Sedation and apnea with benzodiazepines Decrease absorption with high gastric pH Avoid H2-blocker and PPI Take with food Am Fam Physician 2001;63:663-72,677-8 . Primozile – antipsychotics.

Fluconazole Not FDA approval for onychomycosis First line for candida but could use for dermatophytes Check LFT Am Fam Physician 2001;63:663-72,677-8

Prevent recurrence Prevent tinea pedis – powder to feet, protect feet in communal shower, change socks Avoid trauma by tight shoes Ciclopirox nail lacquer 8% (PENLAC) 2 to 3 times a week Topical treatment up to a year to prevent recurrence.

Ciclopirox nail lacquer 8% (PENLAC) Cure rate at 48 weeks – 29% Apply to affected nail and 5 mm of surround skin daily Remove PENLAC with alcohol weekly Remove infected nail frequently

Mechanical removal Surgery Nonsurgical avulsion of dystrophic nail, not normal one The technique removes only grossly diseased or dystrophic nails, not normal nails. Forty percent urea gel (Carmol-40 gel, Vanamide cream) is commercially available or by prescription. Cloth adhesive tape is used to cover the normal skin surrounding the affected nail plate, which has been pretreated with tincture of benzoin. The urea cream is generously applied directly to the nail surface and covered with a piece of plastic wrap. This in turn is covered with a finger that is cut from a plastic glove and held in place with adhesive tape. Patients are instructed to keep the area completely dry with the aid of plastic gloves or booties.

Nonsurgical avulsion Apply 40% urea gel (Carmol-40 gel, Vanamide cream) with occlusive dressing Remove the entire nail or cut the affected portion, followed by curetting to normal nail in 7-10 days Cloth adhesive tape is used to cover the normal skin surrounding the affected nail plate, which has been pretreated with tincture of benzoin. The urea cream is generously applied directly to the nail surface and covered with a piece of plastic wrap. This in turn is covered with a finger that is cut from a plastic glove and held in place with adhesive tape. Patients are instructed to keep the area completely dry with the aid of plastic gloves or booties.

The End