Tinea is a superficial fungal infection of keratin — skin, hair or nails — caused by dermatophytes. It is highly contagious and is named for where it lands: capitis, corporis, cruris, pedis, unguium. The classic lesion is a round, itchy, scaly patch with a raised active edge and a clearing center. Treatment is an antifungal — topical for skin, but oral for hair and nails because a cream cannot reach inside a hair shaft or under a nail. The most-tested nursing action is teaching how to stop the spread.
🍄 A fungus, not a wormDermatophytes eat keratin, so they live in the dead top layer, plus hair and nails. "Ringworm" is a shape, not an animal.
📍 Named by the addresscapitis scalp · corporis body · cruris groin · pedis feet · unguium nails.
💊 Fungus → antifungalSkin = topical "-azole" or terbinafine. Hair or nail = ORAL, for weeks to months.
🚨 Teach: do not shareHIGHLY contagious. No sharing brushes, hats, towels, clothes. Keep skin dry.
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THE SKIN MODEL
STEP 0 · LEARN THIS ONCE
Same skin drawing as every page in this set — this time with fungal filaments living in the dead surface layer.
🔬 Skin cutaway — tinea is the SHALLOWEST of all
DEPTH = THE ANSWER Dermatophytes need keratin to eat, and the only fully keratinised, dead tissue is the stratum corneum — plus hair shafts and nail plates. That is the whole disease in one sentence: fungus lives in dead keratin; the redness and itch are your immune system reacting from below.
🧠 "Fungus is a surface squatter." It never invades living tissue in a healthy person — which is why creams work on skin, and why hair and nails (where creams cannot go) need tablets.
📖 Lesion vocabulary — tinea is a SCALE disease
Tinea produces an erythematous scaly plaque with an annular (ring) shape. "Annular + scaly + clearing center" is exam code for tinea.
🧠 Scale = keratin. Fungus eats keratin, so fungus makes scale. Follow the flakes.
🍄
PATHO & CAUSES
STEP 1 · WHY IT HAPPENS
Warm + damp + contact with fungus = tinea. Get any of those three away and it struggles.
🧠 The one-sentence definition
Tinea is a superficial fungal infection of keratinised tissue — skin, hair or nails — caused by dermatophytes (genera Trichophyton, Microsporum, Epidermophyton). It is highly contagious.
"Ringworm" is a misnomer — there is no worm. The name describes the expanding ring-shaped lesion.
🧠 "Ringworm has no worm, and tinea has no location — until you add the second word."
⚙️ Mechanism, step by step
Fungal spores land on skin — person, animal, soil or object
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Warm + moist + a small break = they germinate
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Hyphae digest keratin and spread OUTWARD through the stratum corneum
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The immune system reacts from the dermis below
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Raised, red, scaly ACTIVE edge + itch
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The center clears as the fungus moves on = the RING
🧠 The ring is a footprint. The edge is where the fungus is now; the middle is where it used to be.
⭐ How people catch it
Person to person — direct skin contact, contact sports
Animal to person — puppies, kittens, calves, guinea pigs (often the more inflamed lesions)
Object to person — brushes, combs, hats, towels, clothing, bedding, gym mats, shared shoes
Soil to person — gardening without gloves
Self-spread — scratching the groin after touching the feet
🧠 "Pedis first, cruris second." Teach patients to put socks on before underwear so they do not carry the fungus from foot to groin.
🌡️ Risk factors — what makes skin friendly to fungus
Heat and humidity; sweating; occlusive shoes and synthetic clothing
Moist skin folds — groin, under the breasts, between the toes
Communal wet floors — showers, changing rooms, pool decks
Topical "-azoles" — clotrimazole, miconazole, ketoconazole. Apply to the lesion plus ~2 cm of normal skin around it
Terbinafine — topical cream, or oral for nails and scalp
Itraconazole / fluconazole — other oral options
Ketoconazole or selenium sulfide shampoo may be used as an adjunct in tinea capitis to reduce shedding — it does not replace the oral drug
Oral agents may need liver function monitoring; check interactions before giving
An antihistamine may be prescribed for the itch — it treats the symptom, not the fungus
🧠 "-azole = a fungus killer." If the drug name ends in -azole or is terbinafine, the stem is about fungus.
✅ Nursing care & comfort
Gloves for direct contact with lesions; hand hygiene before and after
Assess and document the lesion: site, size, shape, border, scale, satellite lesions
Keep nails short and discourage scratching — scratching spreads and can cause secondary bacterial infection
Cool compresses and loose clothing for comfort
Watch for secondary bacterial infection: increasing pain, warmth, pus, fever
Reassure — it is treatable and, in most sites, does not scar
🧠 Scratching turns a fungal problem into a bacterial one.
❌ Never do these
Never treat a suspected fungal rash with a topical steroid alone.
Never stop the antifungal because the itching or the redness has gone.
Never let the patient share brushes, hats, towels or bed linen.
Never expect a cream to cure a scalp or nail infection.
Never give griseofulvin on an empty stomach — it needs fat to be absorbed.
🧠 Don't steroid it, don't stop it, don't share it.
🔀
TELL THEM APART
STEP 4 · THE REAL EXAM SKILL
A ring with a clear center is a fungus until proven otherwise.
🗺️ Where each one shows up
🧠 Rings anywhere warm and damp = tinea. Same body, five patterns.
📊 The look-alikes
CONDITION
HOW IT DIFFERS FROM TINEA
Psoriasis
Silvery, thick scale on extensor surfaces (elbows, knees), well-demarcated but no central clearing. Autoimmune, not infectious. Responds to steroids — tinea does not.
Nummular eczema
Coin-shaped, but solid — itchy, weeping or crusted, with no clear center and no raised scaly ring.
Impetigo
Honey-colored crust, no ring, bacterial → needs an antibiotic.
Cellulitis
Hot, painful, spreading, often febrile, no scale. Bacterial and deep.
Pityriasis rosea
A single "herald patch" then a Christmas-tree pattern of oval scaly patches on the trunk. Self-limiting, viral-associated.
Tinea versicolor
A yeast (Malassezia), not a dermatophyte: fine scaly patches of lighter or darker skin on the chest and back — patchy pigment, no ring.
Nail psoriasis / trauma
Nail changes can be pitting (psoriasis) or a single damaged nail (trauma). Confirm fungus before committing to months of oral therapy.
🧠 Ring with a clear center = fungus. Silver scale on elbows = psoriasis. Golden crust = bacteria.
⭐ NCLEX traps
The priority for tinea is nearly always teaching to prevent spread.
Griseofulvin with a high-fat meal — do not pick "on an empty stomach."
Do not stop when the itching stops — courses run weeks to months.
Scalp and nail infections need ORAL therapy; a cream is the wrong answer.
Scrape the active border, not the cleared center, for the KOH prep.
Recurrent groin tinea? Look at the feet — that is usually the reservoir.
Tinea is not a reason for isolation, but it is a reason to stop sharing personal items.
🧠 If an answer choice mentions sharing personal items or finishing the full course, read it twice.
🧠 One-line contrasts
Tinea vs psoriasis — clearing center vs solid silvery plaque
Tinea vs eczema — ring vs ill-defined itchy patch
Tinea vs impetigo — scale vs honey crust
Tinea capitis vs alopecia areata — scaly with broken hairs vs smooth bald patch
Tinea vs cellulitis — itchy and scaly vs hot and painful
Tinea versicolor vs corporis — pigment patches vs an expanding ring
🧠 Scaly ring, smooth patch, honey crust, hot leg. Four pictures, four diagnoses.
⚡
QUICK RECALL
SAY IT OUT LOUD
💍 Ring with a clear centerRaised scaly ACTIVE edge. Itchy. No worm.
📍 capitis · corporis · cruris · pedis · unguiumScalp · body · groin · feet · nails.
💊 Hair or nail = ORALSkin = topical -azole or terbinafine. Griseofulvin with a HIGH-FAT meal.
🚨 Do not share · keep dryHighest-priority teaching. Don't stop when the itch stops.
🎯 Cover & check — 9 rapid-fire questions
Q1: What actually causes ringworm?
A dermatophyte fungus that digests keratin — not a worm. It lives in the dead stratum corneum, hair shafts and nail plates.
Q2: Describe the classic lesion.
A round, itchy, scaly patch with a raised, more active outer border and a clearing center — the ring.
Q3: Name the tinea of the scalp, body, groin, feet and nails.
Capitis (scalp), corporis (body/ringworm), cruris (groin/jock itch), pedis (feet/athlete's foot), unguium (nails/onychomycosis).
Q4: What is the single highest-priority teaching point?
Prevent the spread — do not share brushes, combs, hats, towels, clothing, bedding or shoes, wash items in hot water, and wash hands after touching lesions.
Q5: Which infections cannot be cured with a cream, and why?
Tinea capitis (scalp) and tinea unguium (nails). The fungus is inside the hair shaft or under the nail plate where topical drug cannot reach, so an oral antifungal is required — for weeks to months.
Q6: How should griseofulvin be taken, and what do you teach about stopping it?
With a high-fat meal, because fat greatly improves absorption. Do not stop when the itching stops — the course runs weeks to months and stopping early causes relapse. Also teach sun protection.
Q7: Where do you take the sample for a KOH prep?
Scrape scale from the active, raised, scaly border. The cleared center may have no organisms. For scalp disease, pluck affected hairs with the root.
Q8: A rash improved on a topical steroid and then spread with a faint edge. What happened?
Tinea incognito — the steroid suppressed the inflammation that was containing the fungus, so it looked better briefly and then spread. It needs an antifungal.
Q9: A patient keeps getting tinea cruris. What do you check?
The feet. Untreated tinea pedis is usually the reservoir. Teach them to treat the feet, dry thoroughly between the toes, and put socks on before underwear.