Classification:

Capitis; scalp

corporis; trunk and extremeties

manuum; palms,soles,interdigital webs

cruris; groin

barbae; beard

faciei; face

unguium(onychomycosis); nail

Preventing dermatophytosis;

• non occlusive footwear and cotton socks

• uring antifungal abserbent powders

• clip nails

• old shoes should be discrarded

Management

• Topical

  • beneficial for common localised dermatophyte infection

  • non-inflamm tinea corporis

    • tinea cruris

    • tinea faciei

    • tinea manuum

    • tinea pedis

  • apply bd to affected area and at least 3cm outside margin

• Systemic

  • higher incidence and increase severity of side effects

  • tinea manuum, pedis - hyperkeratotic lesions more difficult to treat

  • tinea capitis

  • consider:

    • disabling extensive disease

    • intolerant to topical

    • failed topical

    • chronic

    • immunosuppressed

  • Ketoconazole = hepatic side effects

  • terbinifine rarely associated with liver toxicity

Tinea pedis

• more common adults > children

• may be transmitted within the family bathroom

• other dermatophyte infections associated with:

  • especially Tinea cruris

  • onychomycosis

  • tinea manuum

• moist environ created by wearing occlusive shoes = most important

• may be associated with unilateral tinea manuum

• Tinea manuum nearly always associated with tinea pedis

  • scratch feet with hand

  • share clincial features:

    • chronicitiy

    • hyperkeratosis

Onchomycosis

• 50% of nail dystrophy due to onchomycosis

  • dermatophytes: 90%

• associated intertiginous dermatitis

  • tinea pedis

• Occlusion of toe clefts through wearing shoes predisposes to this

  • lateral webspace infection

• confirm diagnosis wiht potssium hydroxide (KOH)

• toe web tinea pedis with maceration = mixed infection

Management

• fingernail infections respond well to oral :

  • terbinafine 250mg/day

  • itraconazole 100mg/day

  • fluconazole 150mg/week

  • for 2-3mo

• toenails longer treatment - 6mo

• exclusive topical antifungals not recommended

• avulsion of nail occasionaly useful in severe disease

• terbinafine >> itraconazole

Dermatophytide

“id reaction”

• noninfective

• cutaneous eryption

• representing allergic repsonse to distant focus of dermatophyte infection

  • usually on feet

• 4-5% of patients wiht tinea pedis

• two forms

  • desquamation of skin of palms

    • simply peels off with no sings of inflmaation or itch

    • most common

  • blistering reaction on soles or hands/both

• palamr and webspace skin may be covered with papules/vesicles

• indistinguishable from constitutional eczema of pompholyx

• diagnosis in this setting:

  • 1. proved dermatophyte infection

       1. usually becomes highly inflammed before appearance of second rash

    2. distant eruption

    3. rash disappears spont. when ring worm infection settles

    4. reactive delayed trichophytin skin test

• systemic treatment usually indicated

• short course of systemic steroids with an iantifungal drug = most helpful

Tinea icognito

Steroid modified tinea

• original infection slowly extends

• dampens down the inflammation

• when cream stopped for a few days

  • itch gets worse -> more steroid -> fungal infection gets worse

• less raised margin

• less scaly

• more pustular

• more extensive

• more irritable

• secondary changes caused by long term use of topical steroids

  • atrophy

  • pupura

  • telangiectasia

• diagnosis;

  • microscopyic visulaisation of branching hyphae and spores

Tinea cruris

• infection in the inguinal region

  • inner aspects of upper thighs and crural folds

  • possible extension onto abdomnen and buttoclks

    • more severe presentations

• Characteristic lesions;

  • sharply demarcated red plaques

  • raised, scaly, advancing border

  • pustules/vesicles

• Doesn’t usually involve scrotum or penile shaft in immunocompetent hosts

• men > women

• warm humid conditions in groin seem important

• obesity + excessive perspiration = predisposing

• Preventativs:

  • wearing loose clothers

  • loose weight

  • drying skin after bathing

  • laundering contaminated clothing

  • topical powders in shoes

• usually associated with tinea pedis

• most common = Trichophyton rubrum

• duration depends on causative agent

Treatment

• Topical therapy often sufficient to control disease in patients with early infections

• Long established infection = terbinafine, azolic agents

• monitor hepatic, renal, haematopoeitic function in patients wiht systemic rx.

• watch out for drug interactions

• symptomatic improvment may require 2-6w

• clinical cure may need >6mo

• terbinagine 125mg bd = 88% cure rate

Candidiasis

• more common in women

• doesn’t have distinct raised margin

• patches:

  • red

  • eroded

  • plycyclic

  • confluent

• Sattellite pustules are numerous

• frayed peeling edge as tiny pustules rupture

Seborrhoeic dermatitis

• common chronic dermatitis

• characterised:

  • redness

  • scaling

• body folds:

  • diffuse

  • exudative

  • sharply marginated

  • bright red eruption

  • usually with fissues

• assopicated with HIV/AIDS

  • 40% HIV +

  • 80% AIDS

  • compared to 3% HIV - population

Erythrasma

• chronic bacterial infection

• Corynebacterium minutissimum

• large

• slightly scaling

• sharply marginated

• brown macules

• Erythema variable

• often absent

• Wood’s light exam -> coral- red fluorescence

Tinea capitis

• Alopecia with scales = most common presentation

• discrete pathces or cover entire scalp

• many will have post. cervical/auricular lymphadenopahty

  • diffuse pustular/grey type

  • helpful in differentiating tinea capitis

• children > adults

• chronic untreated tinea capitus -> scarring alopecia

• contagious

• Oral antifungal required: drug must penetrate hair follicicle

• topical treatment = ineffective

• Trichophyton tonsurans = most common cause

Kerion

• severe pustular eruption with alopecia

• advanced fungal disease with exaggerated host response

• large painful inflammtory, boggy, purulent plaques

• abscess formation

• associated alopecia

• pressure: multiple openings in a honeycomb pattern

• local lymphadenopathy

• secondary bacterial infection rare

• topical agents ineffectual

• oral agents

• until symptoms resovled and culture negative