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Module 12012 lessons

Superficial Fungal Skin Infections

Recognize dermatophyte and candidal disease by tissue and morphology, choose diagnostic testing, deliver site-specific topical or systemic therapy, prevent transmission, and investigate failure or emerging antifungal resistance.

01

Differentiate dermatophyte infection, candidal intertrigo, bacterial disease, inflammatory mimics, and tinea incognito through morphology, site, history, and testing.

02

Choose a diagnostic specimen and method that answers the clinical question before prolonged or systemic therapy.

03

Select and counsel topical allylamine, azole, and formulation strategies for body, groin, feet, and folds.

04

Treat scalp and nail disease through the infected tissue compartment, current product labeling, and measurable safety surveillance.

05

Audit adherence, exposure, reinfection, host factors, steroid use, and diagnosis before labeling a case resistant.

06

Recognize severe or refractory dermatophytosis that may require specialized testing for T indotineae or terbinafine-resistant T rubrum.

120.01

Read the Morphology and Protect the Diagnosis

Dermatophytes infect keratinized tissue, but site names do not prove an organism. Morphology, distribution, exposure, and a properly collected specimen turn pattern recognition into a defensible diagnosis.

What to learn
  • Keratin sites
  • Active border
  • KOH preparation
  • Culture and molecular testing
  • Tinea incognito
Diagnostic mapMove from tissue and morphology to a specimen that can defend the diagnosis
01LocateSkin, hair, or nail

Name the infected compartment

02ReadBorder, scale, moisture, follicle

Describe before treating

03SampleActive edge or diseased tissue

Match specimen to the question

04ReopenAtypical or refractory

Protect mimics and treatment-altered disease

Start with tissue and pattern

Inspect skin, hair, and nails separately. Record border activity, scale, central change, follicular involvement, alopecia, maceration, fissures, nail debris, distribution, symptoms, and treatment history.

Use testing when it changes care

Collect scale from an active edge for potassium hydroxide microscopy. Culture, histopathology, or molecular methods can answer organism, resistance, nail, hair, atypical, or treatment-failure questions. A negative poor specimen does not exclude disease.

Protect the differential

Nummular eczema, psoriasis, contact dermatitis, pityriasis rosea, erythrasma, candidiasis, bacterial infection, and other disorders can imitate tinea. Prominent scrotal involvement, absent scale, unusual pain, systemic illness, or failure should reopen the diagnosis.

Recognize treatment-altered disease

Corticosteroids can reduce redness and itch while fungus spreads. Ask about every cream, including combination products, and look for altered borders, atrophy, striae, pustules, or unexpectedly extensive disease.

0 of 1 answered
01Where should scale usually be collected for a KOH preparation in annular tinea?

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120.02

Treat Body and Groin Disease as Connected Systems

Localized corporis and cruris often respond to topical therapy, but feet, nails, clothing, contacts, animals, and corticosteroid exposure can sustain recurrence.

What to learn
  • Tinea corporis
  • Tinea cruris
  • Topical boundary
  • Reservoir sites
  • Failure audit
Connected reservoirsTreat the plaque, its boundary, and every route back to the skin
01MapBody and groin

Define extent and competing diagnoses

02TreatComplete labeled course

Continue beyond early symptom relief

03InspectFeet and nails

Find autoinoculation reservoirs

04AuditProduct through exposure

Verify before escalating

Treat localized skin disease completely

Use an appropriate labeled topical antifungal over the lesion and beyond its visible edge for the full product-specific duration. Continue as directed even when itch and redness improve early.

Distinguish the groin differential

Tinea cruris often affects upper inner thighs and may spare the scrotum. Candidiasis, erythrasma, inverse psoriasis, irritant disease, and sexually associated emerging dermatophytes require different reasoning.

Find the reservoir

Inspect feet and nails, review household and animal exposure, launder contaminated clothing and towels, reduce shared items, and address moisture and friction. Autoinoculation can reseed treated skin.

Audit before escalating

Confirm diagnosis, product, amount, application boundary, frequency, duration, adherence, reinfection, follicular disease, host factors, and steroid exposure before changing therapy or assuming resistance.

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01What should be checked when tinea cruris repeatedly returns?

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120.03

Treat the Feet and Interrupt Recurrence

Interdigital, moccasin, and inflammatory patterns require attention to the whole foot, footwear, moisture, nails, barrier injury, and bacterial complications.

What to learn
  • Interdigital disease
  • Moccasin scale
  • Fissures
  • Footwear
  • Cellulitis risk
Foot systemSkin, nail, shoe, moisture, sensation, and circulation shape recurrence
01PatternInterdigital, moccasin, vesicular

Choose therapy and vehicle

02DryToe spaces and footwear

Reduce the fungal environment

03ProtectFissure and high-risk host

Prevent bacterial entry

04EscalatePain, pus, fever, spread

Separate cellulitis from tinea

Map the entire foot

Inspect between every toe, the sole, sides, heel, and nails. Maceration, diffuse scale, vesicles, odor, fissures, dystrophic nails, pain, and drainage change the differential and urgency.

Treat environment and skin

Dry carefully between toes, change socks, ventilate and rotate footwear, avoid sharing shoes or towels, and use sandals in communal wet areas. An unmedicated drying powder does not treat fungus. A medicated antifungal powder can treat labeled skin disease when used for its full course; distinguish active ingredient from vehicle.

Protect high-risk feet

Diabetes, neuropathy, vascular disease, edema, immune compromise, and limited self-care increase harm from fissures and delayed infection. Avoid caustic self-treatment and arrange foot care when inspection or application is unsafe.

Escalate bacterial warning signs

Spreading redness, warmth, severe pain, pus, fever, lymphangitis, or systemic illness suggests bacterial complication. Fungal treatment alone is not adequate for cellulitis or an infected ulcer.

0 of 1 answered
01Which finding in tinea pedis needs urgent reassessment?

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120.04

Separate Candida from Other Fold Disease

Intertrigo names inflammation in a fold. Candida is one cause, favored by moisture, friction, antibiotics, metabolic disease, immune compromise, and occlusion.

What to learn
  • Satellite pustules
  • Moisture
  • Erythrasma
  • Inverse psoriasis
  • Driver review
Fold ecologyMoisture and friction interact with organism and host
01ClueSatellite papules or pustules

Support candidal disease

02CompareErythrasma, psoriasis, irritant

Do not equate fold rash with Candida

03ChangeDryness and friction

Treat the local environment

04InvestigateFrequent recurrence

Review metabolic and immune drivers

Read candidal clues

A moist beefy erythematous fold eruption with peripheral satellite papules or pustules supports Candida, but testing can help when morphology, recurrence, or treatment response conflicts.

Keep competing diagnoses visible

Dermatophyte infection, erythrasma, bacterial intertrigo, inverse psoriasis, irritant friction, and allergic contact disease can overlap. Wood lamp examination, KOH, culture, distribution, and exposure history answer different questions.

Match Candida treatment to its indication

Nystatin cream 100,000 units/g is an option for susceptible cutaneous Candida, commonly applied twice daily until healing according to the prescription. It is not a substitute for a dermatophyte treatment. Skin cream must not be used in the mouth, eyes, or vagina. Persistent irritation or failure warrants reassessment and, when appropriate, repeat diagnostic testing.

Change the fold environment

Gently dry, reduce friction and occlusion, use breathable materials, manage incontinence or drainage, and create a sustainable skin-protection plan. Do not place absorbent material that remains wet against skin.

Do not label every inflamed nail fold Candida

Paronychia is nail-fold inflammation, not a synonym for onychomycosis. Chronic disease can follow wet work, irritants, nail cosmetics, cuticle injury, or inflammatory skin disease; yeast or bacterial infection may complicate it. Protect the barrier, reduce the identified exposure, and assess suspected infection. Clinician-directed anti-inflammatory treatment may be appropriate for established inflammatory paronychia. Pus, marked pain, or spreading inflammation needs evaluation rather than automatic antifungal or antibiotic self-treatment.

Investigate recurrence

Review glycemia, obesity, antibiotics, corticosteroids, immune status, and local anatomy when episodes are frequent, severe, or refractory. Recurrence can reveal a systemic or environmental driver.

0 of 1 answered
01Which finding most supports candidal intertrigo?

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120.05

Use Topical Antifungals as Drug Delivery Systems

Allylamines and azoles interrupt ergosterol biology at different enzymes. Active ingredient, organism, infected tissue, formulation, application boundary, and duration must align.

What to learn
  • Squalene epoxidase
  • CYP51
  • Vehicle
  • Application technique
  • Local reactions
Ergosterol and deliveryMatch molecular target to organism, tissue, vehicle, and technique
01SQLEAllylamines

Block squalene epoxidase

02CYP51Azoles

Block lanosterol demethylation

03VehicleCream, solution, spray, powder

Move drug across the right surface

04TeachBoundary, amount, duration

Make exposure executable

Map the pathways

Allylamines such as terbinafine inhibit squalene epoxidase. Azoles inhibit lanosterol 14 alpha demethylase, also called fungal CYP51. Both disrupt ergosterol biology through different targets.

Match spectrum and tissue

Dermatophyte and Candida likelihood, hair or nail involvement, lesion extent, inflammation, and prior exposure determine whether a topical drug is sufficient. Scalp follicle and nail matrix disease usually need a different exposure strategy.

Treat the vehicle as clinical

Creams fit many dry or mildly moist surfaces. Solutions, sprays, or gels can spread through hair or larger areas. Unmedicated powders reduce moisture; medicated antifungal powders can also deliver treatment. Choose around fissures, maceration, dexterity, stinging, coverage, and patient preference.

Read the exact cream label

For Lamisil AT terbinafine 1% cream in people age 12 years or older, the labeled course is once daily for 1 week for body or groin ringworm, twice daily for 1 week between the toes, and twice daily for 2 weeks on the soles or sides of the feet. Ask a clinician for children under 12. These instructions do not transfer automatically to another formulation or brand.

Keep skin treatment in its compartment

This terbinafine cream is not labeled for nails, scalp, or vaginal yeast infection. A short skin course cannot substitute for a nail-specific preparation or systemic treatment of infected hair.

Write operational instructions

Specify clean and dry preparation, exact area, extension beyond the border, frequency, duration, missed-dose response, hand hygiene, adverse effects, and follow-up. Use teach-back rather than relying on a product name.

0 of 1 answered
01What enzyme is inhibited by terbinafine?

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120.06

Choose the Ingredient, Formulation, and Course

An antifungal brand name does not identify one interchangeable regimen. Read the active ingredient, site, age limit, and directions on the exact product.

What to learn
  • Clotrimazole
  • Butenafine
  • Luliconazole
  • Medicated powder
  • Tolnaftate
  • Undecylenic acid
Read the packageIngredient, site, age, and course travel together
01IngredientRead the active drug

One brand may contain different antifungals

02SiteSkin is not nail or scalp

Confirm the formulation reaches the infection

03AgeCheck the particular indication

Luliconazole age limits vary by site

04CourseProduct-specific frequency and duration

Finish the labeled course; reassess failure

Clotrimazole cream uses a longer course

The reviewed OTC clotrimazole 1% cream label directs a thin layer twice daily: 4 weeks for athlete's foot or body ringworm, 2 weeks for jock itch. Children under 2 need clinician direction. Stop and obtain advice for irritation or lack of improvement at those intervals. It is ineffective for scalp or nail infection.

Butenafine offers two toe-web schedules

The reviewed Lotrimin Ultra butenafine 1% applicator product is labeled for interdigital athlete's foot at age 12 or older: twice daily for 1 week or once daily for 4 weeks. Its effectiveness on soles or foot sides is unknown. Children under 12 need clinician advice. Do not extend this specific package's indication or schedule to every product sold under the same brand.

Luliconazole has site-specific pediatric limits

Prescription luliconazole 1% cream (Luzu) is used once daily for 2 weeks for interdigital tinea pedis, or 1 week for corporis or cruris. Apply a thin layer to affected skin and approximately 1 inch of surrounding skin. The labeled age threshold is 2 years for corporis but 12 years for pedis and cruris. Local application reactions can occur; keep it out of the eyes, mouth, and vagina.

A medicated powder can be treatment

Miconazole nitrate 2% antifungal powder is a drug delivery form, not just a drying aid. A reviewed label specifies twice-daily application for 4 weeks for athlete's foot or ringworm and 2 weeks for jock itch. Follow the dispensed label, keep it away from eyes, and do not use it as a scalp or nail cure. Read the actual Drug Facts panel on barrier products. Baza Antifungal lists miconazole nitrate 2% as its active antifungal; petrolatum is an inactive ingredient. Its jock-itch directions are a thin layer twice daily for 2 weeks, with clinician review if irritation occurs or improvement is absent. Children under 2 years need clinician direction; this skin cream does not treat scalp or nail infection.

Tolnaftate is another labeled skin option

The reviewed tolnaftate 1% cream directions are twice daily for 4 weeks for pedis or corporis and 2 weeks for cruris. Under age 2, use requires clinician direction. If irritation occurs or the condition persists, reassess rather than extending treatment indefinitely. Its skin indication does not establish efficacy for nails or scalp.

Separate ketoconazole cream from foam

The reviewed prescription ketoconazole 2% cream uses once-daily treatment for 2 weeks for candidal skin disease, corporis or cruris, and 6 weeks for pedis. Its pediatric safety and effectiveness are not established. Ketoconazole 2% foam instead has a seborrheic dermatitis indication in immunocompetent patients age 12 and older; fungal-infection efficacy is not established for that foam. Do not substitute the foam because its active ingredient matches the cream.

Understand the steroid combination limitation

Clotrimazole/betamethasone cream is labeled for inflammatory tinea at age 17 and older, but routine steroid-antifungal combinations are discouraged in ringworm care. If specifically prescribed, the label uses twice daily for 1 week for corporis/cruris or 2 weeks for pedis; reassess absent improvement then. Maximum durations are 2 and 4 weeks, respectively, with no more than 45 g/week and no occlusive dressing. Avoid diaper use. Steroid exposure can cause atrophy, striae and adrenal suppression; reduced redness alone is not cure.

A nail-shaped applicator does not establish a nail indication

The reviewed undecylenic acid 25% liquid is labeled twice daily for 4 weeks for athlete's foot or body ringworm. Despite a brush that can reach around nails, its directions explicitly state that it is ineffective on nails or scalp. Choose by the infection being treated, not the shape of the bottle or applicator.

0 of 1 answered
01A 7-year-old has confirmed tinea corporis and a prescription for Luzu. Which statement matches its labeling?

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120.07

Treat Hair and Scalp Through the Follicle

Tinea capitis infects the hair shaft and follicle. Systemic therapy is required, while adjunctive shampoo and contact measures reduce transmission but do not replace oral treatment.

What to learn
  • Broken hairs
  • Kerion
  • Griseofulvin
  • Systemic exposure
  • Contact control
Follicular exposureHair shaft infection changes treatment and transmission
01RecognizeScale, broken hair, alopecia

Identify the scalp pattern

02UrgencyTender boggy kerion

Protect against scarring

03SystemicOral antifungal

Reach the infected follicle

04ContainContacts and hair tools

Reduce shared exposure

Recognize the scalp patterns

Scale, alopecia, broken hairs, black dots, pruritus, lymph nodes, and inflammatory plaques can occur. A tender boggy kerion, drainage, pain, fever, or potential scarring needs prompt clinician assessment.

Use systemic therapy

Topical creams do not penetrate the infected hair shaft and follicle sufficiently. Oral griseofulvin, terbinafine, or another clinician-selected systemic antifungal depends on organism, age, formulation, safety, and local practice.

Dose griseofulvin by formulation

Microsize and ultramicrosize products are not milligram-for-milligram substitutes. Review weight, food-dependent absorption, liver disease, porphyria, lupus, reproductive risk, alcohol, warfarin, contraceptive reliability, and duration.

Check the dose against the formulation and source

Specialist capitis regimens can exceed older US label doses. Texas Children's published referral guidance uses microsize griseofulvin 20 to 25 mg/kg/day for about 2 months, versus ultramicrosize 10 to 15 mg/kg/day. These are clinician-directed regimens; the reviewed US microsize label instead lists 10 mg/kg/day for children older than 2 years, and the ultramicrosize label lists about 3.3 mg/lb/day. Document the selected regimen and its source rather than treating these doses as interchangeable.

Calculate the prescribed suspension dose

For an illustrative 20 kg child prescribed microsize griseofulvin 20 mg/kg once daily: 20 kg times 20 mg/kg = 400 mg/day. A 125 mg/5 mL suspension contains 25 mg/mL, so 400 divided by 25 = 16 mL per daily dose. Shake the bottle and measure with an oral syringe. Confirm the prescription and formulation before using the example; it does not determine treatment for an individual child.

Turn precautions into counseling

Griseofulvin is contraindicated in pregnancy, porphyria, and hepatocellular failure. It can reduce warfarin effect and estrogen-containing contraceptive effectiveness; arrange anticoagulation monitoring and reliable pregnancy prevention. Avoid alcohol, address photosensitivity, and review lupus and prolonged-treatment monitoring. The label advises waiting at least 6 months after treatment before fathering a child.

Control transmission

Adjunctive antifungal shampoo may reduce surface spores. Avoid shared combs, hats, bedding, clippers, and towels, identify symptomatic contacts and animal sources, and follow local school and public-health recommendations.

0 of 1 answered
01Why is topical cream alone inadequate for tinea capitis?

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120.08

Confirm and Treat Nail Disease on the Nail Timeline

Onychomycosis means fungal nail infection; tinea unguium refers specifically to dermatophyte nail infection, not to the name of an organism. Trauma, psoriasis, and other nail disorders can mimic it. Confirm fungus, select therapy through extent and risk, and wait for healthy nail growth before judging appearance.

What to learn
  • Diagnostic confirmation
  • Subungual debris
  • Oral terbinafine
  • Liver safety
  • Nail growth
Nail timelineConfirm the organism, manage systemic risk, then wait for growth
01ProveClipping or subungual sample

Exclude nonfungal dystrophy

02SelectExtent, matrix, patient risk

Justify oral or topical therapy

03ProtectLiver and interaction review

Use systemic treatment safely

04MeasureProximal clear growth

Separate slow growth from failure

Confirm before systemic treatment

Obtain a quality nail clipping or subungual specimen for KOH, culture, histopathology, or another suitable method. Sampling strategy depends on the nail pattern and prior antifungal exposure.

Choose through disease and patient

Number of nails, matrix involvement, thickness, pain, function, diabetes, circulation, immune status, liver disease, interactions, adherence, cost, and patient goals determine oral, topical, debridement, or referral strategy.

Use oral terbinafine safely

Current labeling uses 250 mg once daily for 6 weeks for fingernail and 12 weeks for toenail dermatophyte onychomycosis. Confirm disease, exclude chronic or active liver disease, obtain baseline liver tests, and arrange periodic liver monitoring as the label recommends.

Keep alternative oral therapy in context

Fluconazole is an off-label US option for nail infection when standard agents are unsuitable; the April 2026 British Association of Dermatologists leaflet also identifies it as an alternative. The prescriber must select an organism-appropriate regimen and review renal function, pregnancy, interactions, QT risk, and liver safety. Griseofulvin has a nail indication but is generally less useful because of long courses and lower efficacy. Posaconazole has been studied for nails but is not FDA-approved for this indication; historical trial results do not make it a routine replacement for terbinafine or itraconazole. Refractory or unusual-organism cases need specialist reassessment rather than automatic escalation to a broader azole.

Set the right response clock

Healthy nail grows slowly. Photograph or measure proximal clear growth and treat coexisting tinea pedis. Stop oral terbinafine and seek prompt assessment for signs of liver injury, progressive severe rash, or taste or smell loss. New depressive symptoms also require clinical review.

0 of 1 answered
01Why can a toenail remain abnormal after mycologic cure?

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120.09

Deliver Nail Treatment for the Full Growth Cycle

A nail product needs sustained contact with the diseased nail. Confirm the organism and extent, then choose a preparation the patient can apply consistently for many months.

What to learn
  • Ciclopirox 8%
  • Efinaconazole 10%
  • Tavaborole 5%
  • Application technique
  • Long treatment course
Nail deliveryChoose a nail preparation and demonstrate its complete course
01LacquerCiclopirox 8%

Daily coats, weekly removal, professional nail care

02BrushEfinaconazole 10%

Daily for 48 weeks; cover nail and surrounding structures

03DropperTavaborole 5%

Daily for 48 weeks; nail surface and beneath tip

04ReviewGrowth, tolerance, access

Container discard date is not the course end date

Distinguish nail lacquer from skin cream

Ciclopirox 8% nail lacquer is a different preparation from 0.77% skin products. Its labeled role is mild to moderate fingernail or toenail disease due to T rubrum without lunula involvement in immunocompetent patients. Pediatric safety is extrapolated for age 12 and older; pediatric clinical trials were not conducted.

Make the lacquer regimen workable

Apply daily, usually at bedtime, over the affected nail and 5 mm of adjacent skin; reach the exposed underside when possible. Leave coats in place between applications and remove them with alcohol weekly. Wait 8 hours before bathing. Treatment may take 48 weeks and includes professional removal of unattached infected nail, as often as monthly. Diabetes or reduced sensation requires an individualized trimming plan. Avoid nail cosmetics and flames.

Do not assume additive nail benefit

The ciclopirox lacquer label does not recommend concomitant systemic antifungals because the effect of that combination has not been studied. Do not automatically add lacquer to an oral regimen. Discuss modest complete-clearance rates and the long daily commitment before choosing treatment.

Use efinaconazole over the whole treatment surface

Efinaconazole 10% solution (Jublia) treats dermatophyte toenail disease in patients age 6 and older. Apply daily for 48 weeks. Cover the nail, folds, nail bed, hyponychium, and accessible undersurface with the brush. Wait at least 10 minutes after washing or bathing, and apply to clean, dry nails. Persistent irritation, ingrown nail, blistering, or pain warrants review; keep the flammable product away from heat and flames. The effect of nail cosmetics on efficacy is untested.

Distinguish tavaborole from an azole

Tavaborole 5% solution is an oxaborole that interferes with fungal protein synthesis through a tRNA synthetase. For dermatophyte toenail infection at age 6 or older, apply daily over the full nail surface and beneath its tip for 48 weeks. Allow it to dry. Watch for peeling, redness, dermatitis, or an ingrown nail. Keep it away from flames. Check the dispensed package instructions: the reviewed Alembic bottle must be discarded 3 months after the dropper is inserted.

Make a long course feasible

Count the nails requiring treatment, assess reach and hand function, demonstrate the applicator, check supply and cost, and plan refills. A bottle's discard date is different from the treatment end date. Record proximal healthy growth and treatment tolerability; early persistence of old discolored nail does not alone establish failure.

0 of 1 answered
01A patient starts a tavaborole bottle whose label says discard 3 months after inserting the dropper. What does that mean for the 48-week course?

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120.10

Separate Oral Regimens and Interaction Pathways

Choosing an oral antifungal means choosing a specific dosing schedule, absorption requirement, interaction profile, and surveillance plan.

What to learn
  • Terbinafine CYP2D6
  • Itraconazole capsules
  • Pulse versus continuous
  • Heart failure
  • Absorption
Oral treatment checkpointsThe exact drug determines interactions and precautions
01TerbinafineCYP2D6 inhibition

Review interacting medicines and liver risk

02ItraconazoleCardiac and CYP3A4 risks

Heart failure excludes nail treatment

03ScheduleContinuous or fingernail pulse

Verify site and calendar

04PreparationCapsules with a full meal

Address acid suppression; do not substitute oral solution

Do not substitute oral ketoconazole for topical treatment

Ketoconazole tablets are not indicated for skin dermatophyte infection, onychomycosis, or Candida infection. Serious liver injury, including fatal cases, and dangerous drug interactions make them an inappropriate substitute for a topical ketoconazole product in this setting.

Review terbinafine's actual interaction pathway

Terbinafine inhibits CYP2D6. Review susceptible antidepressants, beta blockers, and class IC antiarrhythmics; monitoring or a dose adjustment of the interacting drug may be needed. Do not apply an azole CYP3A4-inhibitor rule to every systemic antifungal. Use at creatinine clearance 50 mL/min or lower is inadequately studied and needs an individualized decision.

Keep itraconazole schedules site-specific

Conventional 100 mg itraconazole capsules: toenail disease, with or without fingernail involvement, uses 200 mg daily for 12 weeks. Fingernails alone use 200 mg twice daily for 7 days, then 21 days off, then another 7-day course.

Check cardiac and interaction exclusions

Do not use itraconazole for onychomycosis with current or previous heart failure or ventricular dysfunction. Review its contraindicated combinations, including simvastatin and lovastatin. CYP3A4 interactions can cause serious toxicity, including arrhythmias. Consider liver monitoring; stop and seek evaluation for liver-injury or heart-failure symptoms.

Match absorption to the preparation

Take conventional capsules whole after a full meal. Acid suppression can reduce absorption and requires a management plan. Capsules and oral solution are not interchangeable.

Address reproductive planning before nail treatment

Do not use itraconazole for nail disease during pregnancy or when planning pregnancy. For patients who can become pregnant, its label requires effective contraception during treatment and for 2 months afterward; begin on menstrual day 2 or 3.

0 of 1 answered
01A patient with prior congestive heart failure receives itraconazole for toenail infection. What is the appropriate action?

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120.11

Investigate Failure and Emerging Resistance

Current CDC guidance highlights T indotineae and terbinafine-resistant T rubrum. Severe, extensive, atypical, or verified treatment-resistant disease may need specialized identification and susceptibility testing.

What to learn
  • T indotineae
  • Resistant T rubrum
  • TMVII
  • Susceptibility testing
  • Stewardship
Failure investigationAudit diagnosis and exposure before moving to specialized resistance testing
01VerifyDiagnosis and complete course

Exclude ordinary failure

02RecognizeSevere, widespread, persistent

Consider emerging dermatophytes

03ReferMolecular and susceptibility testing

Use specialized laboratories

04StewardAvoid steroid combinations

Reduce pressure and delay

Audit common failure first

Reconfirm diagnosis, infected compartment, product, dose, duration, adherence, application, steroid exposure, reinfection, contacts, host factors, and specimen quality. Most failure mechanisms are not proven resistance.

Recognize emerging patterns

T indotineae can produce severe widespread inflammatory plaques and may resist terbinafine. TMVII can produce persistent genital, buttock, or facial lesions linked to intimate contact. Unlike the resistant strains, TMVII is generally not antimicrobial resistant; current CDC evidence supports oral terbinafine, although some patients need itraconazole and prolonged clinician-directed treatment. Terbinafine-resistant T rubrum is also a concern.

Use the right laboratory

Routine laboratories may not distinguish T indotineae from related complexes. Culture, molecular identification, and antifungal susceptibility testing may require a reference laboratory and dermatology, infectious-disease, or public-health coordination.

Protect stewardship

Avoid unneeded steroid-antifungal combinations, incomplete treatment, serial ineffective courses, and unverified systemic exposure. Document treatment precisely and counsel contacts and hygiene without stigmatizing transmission.

0 of 1 answered
01When should emerging resistant ringworm be considered?

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120.12

Close the Loop Across Risk, Interaction, and Life Stage

Topical and systemic antifungal decisions change with age, pregnancy, lactation, liver disease, diabetes, circulation, immune status, drug interactions, access, and ability to complete treatment.

What to learn
  • Product-specific risk
  • Pregnancy narrative
  • Interaction review
  • Teach-back
  • Response targets
Closed-loop careConnect product-specific risk to an observable response and safety plan
01ContextAge, pregnancy, liver, immune

Individualize exposure

02ReconcileDrug and pathway interactions

Name the actual systemic product

03Teach backWhere, how much, how long

Confirm safe execution

04ReturnResponse and toxicity targets

Define the next decision

Use narrative reproductive evidence

Do not use obsolete pregnancy letters. Review human and animal evidence, disease burden, route, exposure area, timing, alternatives, lactation, fertility, and shared goals for the exact product.

Reconcile systemic interactions

Azoles, terbinafine, and griseofulvin affect different enzymes and organ risks. Review prescription drugs, nonprescription products, supplements, alcohol, warfarin, CYP substrates, seizure therapy, contraception, hepatotoxic drugs, and QT risk when relevant.

Adapt to host risk

Children need weight and formulation checks. Diabetes, neuropathy, vascular disease, immune compromise, and liver disease change urgency and safety. Limited dexterity, vision, housing, laundry, or medication access can undermine an otherwise correct plan.

Define success and failure

Set a reassessment interval and track border activity, scale, itch, new lesions, hair or nail growth, contacts, adverse effects, adherence, and test results. State exactly when to stop treatment and seek help.

0 of 1 answered
01What is the safest way to discuss antifungal use in pregnancy?

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Check the connections.

Each attempt draws 10 questions from the complete 50 question bank.

50 questions in this module bank10 questions per attempt

Each attempt draws a fresh set and rearranges the answer choices.

Current clinical foundation.

Core source material was synthesized with the following contemporary guidance. Verify local policy and current guidance before applying clinical information.

  1. CDC Treatment of Ringworm
  2. CDC Emerging Ringworm Clinician Brief
  3. CDC Clinical Overview of Ringworm
  4. DailyMed Terbinafine Tablets
  5. DailyMed Ultramicrosize Griseofulvin
  6. DailyMed Lamisil AT 1% Cream
  7. DailyMed Ciclopirox 8% Nail Lacquer
  8. DailyMed Efinaconazole (Jublia)
  9. DailyMed Tavaborole 5% Solution
  10. DailyMed Itraconazole Capsules
  11. DailyMed Nystatin Cream
  12. Texas Children's Tinea Capitis Referral Guidance
  13. DailyMed Microsize Griseofulvin Suspension
  14. AAFP Tinea Management Pitfalls (2014)
  15. DailyMed Clotrimazole 1% Cream
  16. DailyMed Lotrimin Ultra Applicator
  17. DailyMed Luzu Cream
  18. DailyMed Miconazole Powder Label
  19. DailyMed Tolnaftate Cream
  20. DailyMed Undecylenic Acid Liquid
  21. DailyMed Ketoconazole 2% Cream
  22. DailyMed Ketoconazole Foam
  23. DailyMed Clotrimazole/Betamethasone Cream
  24. British Association of Dermatologists: Chronic Paronychia
  25. DailyMed Baza Antifungal Cream
  26. DailyMed Ketoconazole Tablets: Boxed Warning
  27. BAD Fungal Nail Infections (April 2026)
  28. BAD Onychomycosis Guideline (2014): Alternative Therapy Evidence
  29. Diflucan US Prescribing Information
  30. DailyMed Posaconazole: Indications and Formulations
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