Lecture 5 - Cutaneous Fungal Infections Flashcards
What are the 2 common types of cutaneous fungal infections?
1) Dermatophytes
2) Yeast
What are the 5 infections that are caused by dermatophytes?
1) Tinea corporis - ringworm of body
2) Tinea cruris - jock itch
3) Tinea pedia - athlete’s foot
4) Tinea capitis - scalp
5) Tinea unguium - toenails
What are the 2 infections caused by yeast?
1) Cutaneous candidiasis - occurs in intertriginous areas
2) Pityriasis versicolor
What are the objectives of self-treatment?
- Provide symptomatic relief (itching, burning, and other discomforts)
- Eradicate existing infection and inhibit fungal growth
- Prevent future recurrent infections
When should you refer a cutaneous fungal infection?
If widespread, systemic, recurrent, or persistent
What is the classification of clotrimazole 1%?
Imidazole or azoles
What is the classification of miconazole 2%?
Imidazole or azoles
Are clotrimazole and miconazole fungistatic or fungicidal and what does this mean for treatment?
- Fungistatic
- Will need a longer time-frame for treatment
What are clotrimazole and miconazole used to treat?
Dermatophyte and yeast infection
What is the dosage for clotrimazole and miconazole?
Apply a thin layer morning and evening
What are some adverse effects of clotrimazole and miconazole?
Local skin irritation or hypersensitivity
When should improvement be seen when using clotrimazole and miconazole?
1-2 weeks
Which preparations of clotrimazole and miconazole are most effective?
Cream
What is the classification of tolnaftate?
Thiocarbamate
What is thiocarbamate?
Narrow spectrum antifungal
What is thiocarbamate used to treat?
- Dermatophyte infections
- Ineffective in treatment of cutaneous candidiasis
What is the dosage of thiocarbamate?
Apply morning and evening
What is an adverse effect from thiocarbamate?
Local skin irritation
When should improvement be seen when using tolnaftate?
Greater than 2 weeks
What kinds of preparations is tolnaftate available as?
Cream, gel, aerosol, topical powder, topical solution
What is undecylenic acid used to treat?
Dermatophyte infections
What is the dosage for undecylenic acid?
Apply twice daily
What are some adverse effects experienced from undecylenic acid?
Itching, burning, stinging
What kinds of preparations is undecylenic acid available as?
Ointment, powder, or spray
What is the classification of nystatin?
Polyene
In nystatin fungistatic or fungicidal?
Both
What kinds of preparations is nystatin available as?
Cream or ointment
What is nystatin used to treat?
Candidal infections
What is the dosage for nystatin?
Apply 2-3 times daily
What is an adverse effect experienced from nystatin?
Rarely irritation
What is the classification of ciclopirox?
Hydroxypyridone
What is ciclopirox?
- Broad spectrum agent
- Antimycotic agent effective against dermatophytes, yeast, and some bacteria
What are some adverse effects experienced from ciclopirox?
Pruritus, burning, erythema
What is the dosage for topical ciclopirox?
Apply to affected area twice daily for 4 weeks
When should improvement be seen when using topical ciclopirox?
- After 1 week, relief of itching and other symptoms should occur
- If after 2 weeks there is no clinical improvement, re-evaluate diagnosis
What kinds of preparations is ciclopirox available as?
- Loprox - 1% cream/lotion
- Stieprox - 1.5% shampoo used 2-3 times/week for treatment of fungal infections associated w/ seborrheic dermatitis
What is the classification of terbinafine?
Allylamine
What is terbinafine?
- Broad spectrum fungicidal agent
- Fungicidal to dermatophytes but only fungistatic to candida
What kinds of preparations is terbinafine available as?
Oral tablet, cream, or spray
What is the advantage to topical terbinafine?
- Generally shorter treatment regimens
- Results in slightly higher cure rate than other topical options
What is the dose for topical terbinafine?
Apply to affected area once daily for 1 week
What are some adverse effects experienced from topical terbinafine?
Pruritus, irritation/burning, rash, dryness
What is oral terbinafine used for?
Fungal nail infections, or severe tinea skin infections where topical treatment has failed
What is a disadvantage to oral terbinafine?
Tablets may interfere w/ cytochrome P450
What are some adverse effects to oral terbinafine?
- Headache
- GI disturbances
- Hepatic failure
- Rash
What is the classification of ketoconazole?
Imidazole
Is ketoconazole broad or narrow spectrum?
Broad
What is a disadvantage to oral ketoconazole?
Risk of potentially fatal liver toxicity, and therefore should only be used for serious or life threatening systemic fungal infections
What does a ringworm infection look like?
- Inner skin appears healthy
- Outer ring is inflamed, red, and scaly
What are some characteristics of dermatophytes?
- Require keratin for growth/proliferation
- Restricted to scalp, nails, and superficial skin
Where is keratin found?
In the cornified human epidermis-stratum corneum
Do dermatophytes have mucosal involvement?
No
How are dermatophytes generally spread?
- Person to person contact
- Soil to human
- Animal to human
- Indirectly from formites (ex: furniture, hairbrushes, hats)
What are the most common dermatophyte pathogens in skin infections?
- Trichophyton
- Microsporum
- Epidermophyton
What age group does tinea pedis generally occur in?
- Adults 15-40
- Children under 12 is unusual and requires referral
Does tinea pedis affect men or women more often?
Men
What are the risk factors for tinea pedis?
- Heat and dampness
- Occlusive foot wear
- Use of public bathing facilities (pools, gyms, dorms)
- High impact sports; marathon runners
- Sharing footwear
- Prolonged application of topical steroid b/c blocks immune response
- Hyperhidrosis (excessive sweating)
What are the common affected areas of tinea pedis?
- Toe webs, especially between 4th and 5th toes b/c generally have most squishing and friction
- May spread between 3rd and 4th toes or to soles of feet
What are the signs and symptoms of tinea pedis?
- Interdigital maceration at web space
- Fissuring and scaling
- Pruritus and/or stinging sensation
- Malodour
When should a patient be referred for tinea pedis?
- Patient is at risk of delayed wound healing (diabetes, cancer, PVD< immunocompromised, elderly, malnourised)
- Child less than 12 years old
- Lesion is weeping or severely inflamed, oozing, eczematous, or painful
- Toenail is affected
What are the subtypes of tinea pedis?
- Chronic interdigital type - most common type; generally self-treatable
- Vesicular type - pruritic vesicles on instep of one or both feet; may be painful; most common in summer months
- Mocassin - off-white scaling lesion of soles and sides of feet; generally found on both feet and often involves nails
- Acute ulcerative type - macerated, weepy lesions on soles of foot; often involving secondary infection w/ gram neg bacteria
What some non-pharms for tinea pedis?
- Proper footcare/hygiene
- Avoid occlusive and tight-fitting footwear
- Change to dry socks 2-3 times/day
- Allow shoes to dry for 48-72 hours
What is the pharmacological treatment for tinea pedis?
- Topical antifungal (1st line is OTC imidazoles)
- BID for up to 4 weeks
- Apply to area and 1-2 cm surrounding
- Refractory cases (or nail infection) require Rx treatment
Which prescription products can pharmacists prescribe for tinea pedis?
- Ciclopirox and terbinafine
- Salicylic acid and tolnaftate are available OTC and are not first line treatment
Why is prompt treatment important for tinea pedis?
To prevent individuals from developing tinea unguium or infections in toenails
Is there any OTC treatment for onychomycosis?
No
When should you refer for onychomycosis?
Immediately
How is the diagnosis of onychomycosis confirmed?
Nail clippings, scrapings under the nail, and deep nail samples
What is the prescription treatment for onychomycosis?
- Oral terbinafine for 12-16 weeks for toenail, or 6 weeks for fingernail
- Ciclopirox nail lacquer, daily application for 48 weeks
What is a side effect to oral terbinafine for onychomycosis?
Risk of severe liver injury
What is a disadvantage to ciclopirox nail lacquer?
Limited penetration into the nail
What are the areas affected by tinea cruris?
- Bilateral thighs
- Inguinal folds
- Buttocks
- Gluteal cleft (less common)
- Can affect external vaginal area in females, but less common
What are the risk factors for tinea cruris?
- Warm, humid condition or increased sweating
- Wearing wet or multiple layers of clothing
- Immunocompromised individuals
- Prevalence greater in men than women
Can one partner transmit tinea cruris to another?
Yes
What are the signs and symptoms of tinea cruris?
- Well marginated erthymatous half-moon plaque
- Small vesicles may be seen
- Quite pruritic
- Acute lesions are bright red
- Chronic cases tend to have more hyperpigmented appearance
What is the differential diagnosis for tinea cruris?
- Pubic lice
- Both appear as itchy and erythematous
- For pubic lice, skin may appear bluish and spotted
- For tinea cruris, round or irregular shaped patches will appear
When would you refer a patient for tinea cruris or tinea corporis?
- Infection has unknown origin
- Immunocompromised
- Responding poorly to topical therapy
- Disease is extensive, disabling, multifocal, or inflammatory
What is tinea corporis?
Ringworm of the body
What are common risk factors for tinea corporis?
- Most commonly seen in pre-pubescent individuals (children in daycares, schools)
- Exposure to contaminated soils
- Exposure to infected animals or people
- Warm and moist environments
- Shared towels or clothing
What are the signs and symptoms of tinea corporis?
- Often occurs on skin of trunk, face, and extremities
- Oval, ring-like, erythematous, scaly patches
- Reddened edges and sharp margins
- Itching is variable
What is the differential diagnosis for fungal skin infections?
- Contact dermatitis or bacterial skin infections
- Fungal skin infections occur on areas w/ excess moisture, which the others occur anywhere on the body
How can tinea corporis be prevented and managed?
- Use general non-drug measures (loose fitting clothing, powder to reduce moisture)
- Topical antifungal (imidazoles are 1st line treatment)
- For refractory or resistant cases - allylamines or oral Rx agents
What is the dosing for imidazoles in the treatment of tinea corporis?
- Twice daily for 4 weeks (in the morning and at bedtime)
- Apply to normal skin 2 cm beyond the affected area
- Tolnaftate and undecylenic acid are also options
What is tinea capitis?
- Fungal infection involving scalp hair follicles
- May extend to eyebrows, eye lashes, and beard
- Occurs most often in children
- Visible “black dots”
Why aren’t corticosteroids used for treatment of fungal skin infections?
They will suppress the immune system and allow fungus to overgrow
What is pityriasis versicolor?
Infection of stratum corneum by Malassezia
Where and in who does pityriasis versicolor occur most often?
- Upper trunk (sebaceous glands)
- Highest incidence in tropical environments, adolescents, and young adults
When would you refer pityriasis versicolor?
If causation unclear
What are the signs and symptoms of pityriasis versicolor?
- Change in cutaneous pigmentation, lesions may be hyper or hypopigmented
- Lesions occur on back, chest, and upper arms
- Individual lesions small but can coalesce to form
- No itching
What is the OTC treatment for pityriasis versicolor?
- Selenium sulfide 2.5% shampoo (apply for 10 mins, then wash off once daily for 7-14 days; use 1-2 times/month for prevention)
- Topical azole cream (apply BID for 2 weeks)
- Ketoconazole 2% shampoo (leave on for 5 mins then wash off once daily for 3 days)
Is recurrence common for pityriasis versicolor?
Yes
What causes candidiasis?
Candida albicans
What are risk factors for candidiasis?
- Diabetes
- Immunosuppression
- Tropical environment
- Poor hygiene
- Psoriasis/contact dermatitis
- Obesity
- Individuals w/ hands in water excessively
What are the typical affected areas of candidiasis?
- Groin
- Armpit
- Gluteal region
- Under breasts
- Skin folds (abdominal region)
- Hands
What is the presentation of candidiasis?
- Bright red
- Moist skin surface
- Scaling borders and satellite (no clear border) papules or pustules
When would you refer for candidiasis?
- Unsuccessful initial treatment or condition worsens
- Condition extensive, seriously inflamed, or debilitating
- Systemic or recurrent infection
- Signs of secondary bacterial infection
- Immunocompromised
- Patient less than 2 years old
What is the management for candidiasis?
- Keep area dry (non-medicated powder; avoid cornstarch)
- Topical antifungal OTC (imidazoles BID for 2-3 weeks or nystatin cream BID-TID for 2-3 weeks)
- In more severe cases, may use combination therapy - OTC topical antifungal and topical corticosteroid, Rx topical or oral antifungal therapy
When can imidazoles be used?
- Superficial dermatophyte infections
- Candida/mixed
When should nystatin be used?
Candida infections
What is a monitoring parameter for cutaneous fungal infections?
1-2 week improvement w/ relief of pruritus
What is Desenex in Canada?
Undecylenic acid
What is Lotriderm in Canada?
Clotrimazole and betamethasone (Rx)
What is fungi-cure/fungi-nail product used for?
Athlete’s foot or ringworm of body/groin
What is the downside to tea tree oil as a treatment for cutaneous fungal infections?
Needs to be used as BID application for 6 months, which is not practical and not entirely guaranteed
Can clotrimazole be used in pregnancy and breastfeeding?
Yes
Can miconazole be used in pregnanacy?
No
Can miconazole be used in breastfeeding?
Yes
Can nystatin be used in pregnancy and breastfeeding?
Yes
What is the minimum age of used for clotrimazole, miconazole, tolnaftate, and undecylenic acid?
2 years
How can a patient prevent the spreading of a cutaneous fungal infection to other parts of the body?
- Use separate wash cloth and towel to wash/day affected area
- Use hair dryer at low heat to dry intertriginous spaces that towel can’t reach
- Put socks on before underwear to avoid spreading tinea pedis to groin
- Avoid wearing clothing and shoes that allow the skin to stay wet
- Allow shoes to dry thoroughly before wearing them again
When should tinea pedis be completely treated?
4 weeks
What is the treatment guideline for tinea cruris?
BID for 2-4 weeks
What is the treatment guideline for tinea corporis?
BID for 4 weeks
What is the treatment for candida intertrigo?
BID for 2-3 weeks
What is an important note to mention to patients being treated for cutaneous fungal infections?
Continue treatment for 1-2 weeks after symptom resolution to ensure full eradication and prevent relapse
What are tolnaftate and undecylenic acid used to treat?
Tinea pedis only
What is diaper dermatitis?
A form of contact dermatitis due to disruption of normal skin barrier from moisture, friction, urine, and feces
What are the signs and symptoms of irritant diaper dermatitis?
- Shiny red patches in diaper area
- Folds of skin are not affected (this can help differentiate btwn candidiasis which is almost always seen in skin folds)
What are the risk factors for diaper dermatitis?
- Irritants and friction
- Comorbid conditions - atopic dermatitis
- Chemicals
- Type of diaper used
- Occlusion and humidity
When would you refer for diaper dermatitis?
- Lack of improvement after 7 days of treatment
- Pain, itching, or inflammation increases
- Area shows signs of infection
What are the goals of therapy for diaper dermatitis?
- Relief of symptoms
- Resolution of dermatitis
- Prevention of complications and recurrences
What are some non-pharms for diaper dermatitis?
- Bathe daily in lukewarm water
- Use fragrance free soap
- Dry diaper area by patting gently
- Fragrance and alcohol free baby wipes
- Increase frequency of diaper changes
- Do not use talc powders
What are the pharmacological treatment options for diaper dermatitis?
- Barrier products
- Zinc oxide
____ are desirable as barriers
Pastes w/ more than 10% zinc oxide, titanium dioxide, starch, or talc
What are the 2 types of barrier products?
1) Water impermeable
2) Barrier and water-absorptive
What are some water impermeable barrier products?
- Petrolatum
- Dimethicone or dimethylpolysiloxane
- Anhydrous lanolin or anhydrous eucerin
Which concentrations of zinc oxide are used for which purpose in diaper dermatitis treatment?
- Lower concentrations (15%) used for prevention
- High concentrations (>25%) used for treatment
When would antifungal treatment be used for diaper dermatitis?
- Moderate to severe cases
- Apply first and then apply barrier cream
- Apply twice daily for 1 week, stop when clear
When would topical corticosteroids be used for treatment of diaper dermatitis?
- Under supervision of a physician for children under 2 years old
- Used in cases where allergic contact dermatitis is suspected
