Superficial fungal infections (Fungal skin infection)

Question 1

Background

Answer 1

Superficial fungal infections: affect the outer layers of the skin, the nails and hair:
- Dermatophytes (tinea)
- Yeasts (candida, yeasts, moulds)

Tinea - Dermatophyte infection, depending on which part of the body is affected, is given a specific name. Sometimes named on appearance

Question 2

Signs and Symptoms / Diagnosis

Answer 2

Scalp - scaling, itching, hair loss patches, skin erythema, pustules

Nail - abnormal look, discoloured, thickened nail, white/yellow streaks.

Foot - scaling, small vesicles/blisters, itchy, flaky, painful.

Body & Groin - scaly, itchy skin, single/multiple red raised skin patches, lesions.

Diagnosis:
Examination of symptoms (identify type of infection)
- Microscopy
- Culture

Question 3

Treatment (Non Pharmacological)

Answer 3

self-care management
- Wear loose-fitting clothes - cotton or material designed to keep moisture away.
- Maintain good hygiene by washing - After washing dry thoroughly,
- Avoid scratching affected skin
- Do not share towels, and wash them frequently, to reduce the risk of transmission.
- Wash clothes and bed linen frequently to eradicate fungal spores.
- If a child is affected, not needed to miss school or nursery.
- Soften any surface crusts, and then gently tease away.
- Discard or disinfect objects that can transmit fungal spores, eg clothes, hairbrushes, pillows, blankets, and scissors, to prevent re-infection or transmission of infection to others.
- Parents or carers should inspect the scalps of other children and household contacts regularly for clinical signs of infection
- If a household pet is sus of being the source of infection, should be assessed and treated by a vet.
- Avoid trauma

Question 4

Treatment (Pharmacological)

Answer 4

FOOT + Body & Groin
Topical antifungal cream (terbinafine, imidazoles [clotrimazole, miconazole, econazole])
ALT OTC undecanoic cream or topical prep with tolnaftate.
Can + mild-potent corticosteroid if marked inflammation (hydrocortisone 1% OD 7 days)

Severe/extensive
FOOT = Oral antifungal (1st line terbinafine ALT itraconazole or griseofulvin) - ADULT. Child - refer
B&G = refer

Scalp
Oral antifungal (griseofulvin or terbinafine) -empirical
After culture results:
Trichophyton = terbinafine
Microsporum = Griseofulvin
ALT itraconazole 4 week

Can give topical anti-fungal = reduce spread (ketoconazole shampoo 2/7 - 2–4 weeks, or imidazole cream (children< 5 years) daily for 1 week.

Nail infection
Dermatophyte or Candida confirmed:
- topical amorolfine 5% nail lacquer OTC 1-2/7 after nail filing. 6 months for fingers 9-12 for toes. IF FAIL =

Confirmed dermatophyte
Oral antifungal
1st line terbinafine 250mg OD 6 weeks finger 12-24 toes.
ALT itraconazole 200mg BD 1 week repeat course after 21 days finger - 2 courses toes - 3 courses.

Confirmed candida or non dermatophyte
1st line oral itraconazole (same regimen as above)
ALT oral terbinafine (same regimen as above)

If both drugs need ALT then try Topical antifungal (eg amorolfine)

Question 5

Drug info

Answer 5

Topical amorolfine (nail):
Avoid contact with eyes, ears, mucous membranes, naked flames.
AE - Burning sensation, itching

Topical antifungals: (B&G, Foot, scalp)
Contraindications and cautions -
Terbinafine 1% cream B&G >12 yrs
topical imidazoles - avoid contact with eyes, ears, mucous membranes,
AE - Burning sensation, itching

Oral terbinafine (All types):
Contraindications - Hepatic impairment LFT b4 treatment, severe renal impairment.
AE- GI, nervous, skin, anaphylaxis
Interactions -
- It increases levels of B-blockers, MOI-B, SSRIs, TCA, Anti arrhythmic tramadol, Dextromethorphan, Aripiprazole, risperidone.
- Its levels are increased by Amiodarone, Fluconazole, ketoconazole.
- Tamoxifen, rifampicin (terb.. levels reduced), Codeine (analgesic effect reduced)

Oral Itraconazole (ALL types):
Contraindications - Acute porphyria , Ventricular dysfunction or Hx HF
AE - GI, nervous, skin, hepatobiliary interactions - Itraconazole is metabolized by the cytochrome p450 3A4 so interacts with a number of liver enzyme-inducing and liver enzyme-inhibiting drugs
Key I (avoid) -
increases levels of: Statins, Domperidone, Ranolazine/ Pimozide = (increase QT), Eplerenone, Ivabradine, Ergot alkaloids, Disopyramide, Corticosteroids, PDE-5 i,
Its levels reduced by: St John’s wort

Oral griseofulvin (B&G, Scalp, foot)
Contraindicated - Acute porphyria,
Severe liver disease,
Systemic lupus erythematosus
AE - GI, Skin, hepatobiliary,
Interactions - Alcohol (disulfiram-like reaction (flushing, tachycardia)
Oral contraceptives (efficacy reduced), Warfarin (can decrease INR), Phenobarbital/ Primidone - reduced levels of grise..)