Dermatology Book

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Onychomycosis

Aka: Onychomycosis, Tinea Unguium
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  1. Definition
    1. Fungal infection affecting the Toenail or Fingernail
  2. Epidemiology
    1. Prevalence: 10% of population affected worldwide
    2. Most common Nail Disorder (accounts for 50% of Nail Disorders)
    3. Rarely occurs in children unless predisposing factors
      1. Immunosuppression (e.g. AIDS)
      2. Extensive fungal skin involvement
      3. Family History of Onychomycosis
  3. Pathophysiology
    1. Person to person transmission
  4. Risk Factors
    1. Older age (especially over age 60 years)
    2. Tinea Pedis
    3. Swimming
    4. Psoriasis
    5. Immunodeficiency
  5. Types
    1. Distal Subungual (most common)
      1. Affects distal and lateral Toenails and Fingernails
      2. Associated with Tinea Pedis
      3. Most common etiology: Trichophyton rubrum
    2. White superficial Onychomycosis (10% of cases)
      1. Most common etiology: Trichophyton mentagrophytes
      2. May affect entire Toenails
        1. Starts as opaque, well demarcated white spots
        2. Spots coalesce to involve entire nail
    3. Proximal Subungual (least common)
      1. Most common etiology: Trichophyton rubrum
      2. Affects proximal Fingernails and Toenails
      3. Fungi invade proximal nail fold to enter nail
      4. Predisposing factors
        1. Immunocompromised status (e.g. AIDS)
        2. Local trauma
    4. Candida Onychomycosis (rare)
      1. Associated with Chronic Paronychia (Candida)
      2. More common in immunocompromised state
    5. Total dystrophic Onychomycosis
      1. Total nail plate destruction from above types
  6. Signs: Nail plate changes
    1. Discoloration (white or yellow)
    2. Opacification
    3. Distribution based on type (see above)
  7. Labs
    1. Potassium Hydroxide (KOH): Subungual debris scraping
      1. Test Sensitivity: 80%
      2. Test Specificity: 72%
    2. Nail Biopsy: Periodic acid schiff stain (effective, but expensive and not widely available)
      1. Test Sensitivity: 92%
      2. Test Specificity: 72%
    3. Fungal Culture
      1. Efficacy
        1. Test Sensitivity: 59%
        2. Test Specificity: 82%
      2. Distal subungual Onychomycosis
        1. Clip nail short
        2. Apply curette to nail bed near cuticle for sample
        3. Also scrape underside of nail plate
      3. White superficial Onychomycosis
        1. Scrape nail plate surface white area for sample
      4. Proximal superficial Onychomycosis
        1. Pare nail plate near lunula
        2. Curette sample from infected nail bed
      5. Candidal Onychomycosis
  8. Differential Diagnosis
    1. Only 50% of Dystrophic Nails are Onychomycosis
    2. Candida Paronychia (Chronic Paronychia)
    3. Bacterial Paronychia (Acute Paronychia)
    4. Herpetic Whitlow (Herpes Simplex Virus)
    5. Psoriasis
    6. Lichen Planus
    7. Contact Dermatitis
    8. Local nail trauma
    9. Nail bed tumor
    10. Yellow Nail Syndrome
  9. Management: General Measures
    1. Keep feet dry
      1. Wear cotton socks and change 2-3 times per day
      2. Wear shoes that are breathable
    2. Reduce fungus exposure
      1. Wear foot protection in shared showers (locker room)
      2. Treat Tinea Pedis
    3. Consider nail removal in severe Onycholysis
    4. Optimize chronic disease management
      1. Diabetes Mellitus
      2. Tobacco Cessation
    5. Antifungal Medications
      1. Consider Topical Antifungal as adjunct to those below
      2. Consider longer Antifungal course in some patients
        1. Slow Nail Growth
        2. Extensive nail plate involvement
        3. Diminished blood supply
          1. Peripheral Vascular Disease
          2. Diabetes Mellitus
  10. Management: Antifungal agents
    1. Terbinafine (Lamisil)
      1. See Terbinafine for dosing and monitoring
      2. Most effective oral Antifungal agent for treatment of Onychomycosis
      3. Cure rate: 79-84%
        1. Dose used: 250 mg daily for 3 months
        2. Evans (1999) BMJ 318:1031-5
        3. Faergernann (1995) J Am Acad Dermatol 32: 750-3
    2. Itraconazole (Sporanox)
      1. See Itraconazole for dosing and monitoring
      2. Cure rate: 64-72%
        1. Dose used: 400 mg/dose intermittently for 3-4 months (72% cure rate was for the 4 months of treatment)
        2. De Doncker (1996) Arch Dermatol 132:34-41
    3. Fluconazole (Diflucan)
      1. See Fluconazole for dosing and monitoring
      2. Cure rate: 62%
        1. Dose used: 450 mg weekly for up to 12 months
        2. Scher (1998) J Am Acad Dermatol 38:S77-S86
  11. Management: Ineffective agents (avoid these)
    1. Griseofulvin
      1. Low cure rates (30-45%) even when taken for up to 6-12 months at 500-1000 mg daily
      2. Faergernann (1995) J Am Acad Dermatol 32: 750-3
    2. Ciclopirox (Penlac)
      1. Topical agents are not effective in Onychomycosis
      2. Requires 48 week application
      3. Marginally better than Placebo
  12. Prognosis
    1. Recurrence rate: 20-50%
  13. References
    1. Gilbert (1999) Sanford Guide to Antimicrobials
    2. Andrews (2008) Am Fam Physician 77(10): 1415-20
    3. Crawford (2002) Arch Dermatol 138: 811-6
    4. Crissey (1998) Postgrad Med 103(2):191-205
    5. Gupta (1997) Dermatol Clin 15(1):121-35
    6. Harrell (2000) J Am Board Fam Pract 13:268-73
    7. Rodgers (2001) Am Fam Physician 63(4):663-72
    8. Scher (1999) J Am Acad Dermatol 40:S21-6
    9. Weinberg (2003) J Am Acad Dermatol 49:193-7

Onychomycosis (C0040261)

Definition (MSH) A fungal infection of the nail plate, usually caused by a DERMATOPHYTES; YEASTS; or nondermatophyte MOLDS.
Concepts Disease or Syndrome (T047)
MSH D014009
ICD9 110.1
ICD10 B35.1
SnomedCT 266215006, 154397004, 186988000, 402134005, 30757001, 414941008, 266149008
English Onychomycoses, ONYCHOMYCOSIS, Dermatophytic onychia, OM - Onychomycosis, Fungal infection of nail, NOS, Fungus, Nail, Nail Fungus, Nail tinea, Onychomycosis (& [tinea of nail]) (disorder), (Nail: [dermatophytosis] or [fungal infection]) or (onychomycosis) or (tinea unguium) (disorder), dermatophytosis of nail, fungal infection of nail, dermatophytosis of nail (diagnosis), fungal infection of nail (diagnosis), Nail fungal infection NOS, NAIL INFECTION FUNGAL, Ringworm of nails, Onychomycosis [Disease/Finding], Tinea Unguium, nail tinea, Infection;fungus;nail(s), onychomycoses, dermatophytic onychia, Onychomycosis, Onychomycosis due to dermatophyte (disorder), Onychomycosis due to dermatophyte, onychomycosis, dermatophytic; onychia, dermatophytosis; nail, fungus; infection, nail, infection; fungus, nail, nail; dermatophytosis, nail; ringworm, onychia; dermatophytic, ringworm; nail, tinea; unguium, unguium; tinea, (Nail: [dermatophytosis] or [fungal infection]) or (onychomycosis) or (tinea unguium), Fungal nail infection, Onychomycosis (& [tinea of nail]), Tinea of nail - onychomycosis, Tinea unguium (disorder), Dermatophytosis of nail, Tinea unguium, Fungal infection of nail, Tinea of nail, Onychomycosis (disorder), Dermatophytosis of nail (disorder), Ringworm of nail, fungal nail infection, tinea unguium
French ONYCHOMYCOSE, Infection fongique de l'ongle, Onyxis fongique SAI, Onyxis dermatophytique, Teigne de l'ongle, Dermatophytose unguéale, Onychomicose, Dermatophytose de l'ongle, Onychomycose, Mycose de l'ongle, Mycose unguéale, Tinea unguium
Portuguese ONICOMICOSE, Infecção micótica da unha, Onicomicose NE, Fungo de Unha, Fungo de Unhas, Tinha das unhas, Dermatofitose ungueal, Tinha da unha, Micose Ungueal, Micoses Ungueais, Micose de Unha, Onicomicose, Tinha das Unhas
German ONYCHOMYKOSE, Pilzinfektion der Naegel NNB, Pilzinfektion des Nagels, Ringwurm der Naegel, Dermatophytose der Naegel, Tinea der Naegel, Onychomykose, Tinea unguium
Dutch nagelschimmelinfectie NAO, schimmelinfectie van de nagel, dermatofytose van nagel, tinea unguium, nageltinea, ringworm op nagels, dermatofytisch; onychia, dermatofytose; nagel, fungus; infectie, nagel, infectie; fungus, nagel, nagel; dermatofytose, nagel; ringworm, onychia; dermatofytisch, ringworm; nagel, tinea; unguium, unguium; tinea, onychomycose, Mycose, onycho-, Onychomycose, Tinea unguium
Italian Infezione micotica dell'unghia, Infezione micotica ungueale NAS, Tigna ungueale, Dermatofitosi dell'unghia, Tigna dell'unghia, Tinea Unguium, Tinea delle unghie, Onicomicosi
Spanish Infección de la uña por hongos, Infección ungueal por hongos NEOM, Hongo de Uñas, Hongo de Unas, Hongo de Uña, Hongo de Una, onicomicosis debido a dermatofito, dermatofitosis ungueal, dermatofitosis ungueal (trastorno), tiña ungueal, onicomicosis debido a dermatofito (trastorno), Onychomycosis (& [tinea of nail]), Dermatophytosis of nail, Fungal infection of nail, (Nail: [dermatophytosis] or [fungal infection]) or (onychomycosis) or (tinea unguium), Tinea of nail - onychomycosis, Onychomycosis, Fungal nail infection, Tinea unguium, Tiña ungueal, Tiña de las uñas, Dermatofitosis de uña, Micosis de Uña, Micosis Ungueales, Micosis de Una, Micosis Ungueal, infección fúngica de la uña, oniquia dermatofítica, tiña de las uñas, tiña de uña, tiña ungular, onicomicosis (trastorno), onicomicosis, infección micótica de la uña, onicomicosis por dermatofito (trastorno), onicomicosis por dermatofito, Onicomicosis, Tinea Unguium
Japanese 爪部真菌感染, 爪真菌感染ＮＯＳ, ｿｳﾌﾞｼﾝｷﾝｶﾝｾﾝ, ﾂﾒｼﾝｷﾝｶﾝｾﾝNOS, ｿｳｼﾝｷﾝｶﾝｾﾝNOS, ﾂﾒｼﾝｷﾝｼｮｳ, 爪の皮膚糸状菌症, ﾂﾒﾉﾋﾌｼｼﾞｮｳｷﾝｼｮｳ, ﾂﾒﾊｸｾﾝ, ｿｳﾊｸｾﾝ, 爪甲真菌症, 爪真菌症, 爪白癬, 白癬-爪, 爪真菌症(ツメシンキンショウ)
Swedish Nagelsvamp
Czech tinea unguium, onychomykóza, Mykotická infekce nehtu NOS, Mykotická infekce nehtu, Onychomykóza, Dermatofytóza nehtu, Plísňové onemocnění nehtu
Finnish Kynsisilsa
Russian DERMATOMIKOZ NOGTEVOI, KANDIDOZ NOGTEVOI, ONIKHOMIKOZ, ДЕРМАТОМИКОЗ НОГТЕВОЙ, КАНДИДОЗ НОГТЕВОЙ, ОНИХОМИКОЗ
Korean 손발톱 백선증
Polish Grzybica paznokci
Hungarian köröm dermatophytosisa, Köröm gombás fertőzése, Köröm gombás fertőzése k.m.n., Köröm bőrgombája, Tinea unguium, Onychomycosis, köröm tinea
Sources
Derived from the NIH UMLS (Unified Medical Language System)


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