Impetigo is a very common, highly contagious superficial bacterial skin infection of infants and children, caused by Staph aureus and/or Group A Strep. Itchy red sores around the nose and mouth burst and dry into the unmistakable honey-colored crust — and that crusting stage is when it spreads fastest, by hands, towels, linen and toys. Nursing care is half skin care and half stopping the spread, plus one safety-net: strep in the skin can later reach the kidneys.
🍯 Honey-colored crustThe single most recognizable sign in dermatology. Golden, stuck-on crust around the nose and mouth of a child.
🚨 HIGHLY contagiousDirect contact and objects — towels, linen, toys, clothes. The crusting stage is the most contagious.
🦠 Staph or StrepSuperficial — top of the epidermis only, so it heals without scarring (except the deep form, ecthyma).
🏫 Home from schoolOff school/daycare, hand hygiene, separate laundry in hot water, short nails, gently soak crusts off.
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THE SKIN MODEL
STEP 0 · LEARN THIS ONCE
Same skin drawing as every page in this set — this time with a shallow blister forming right under the surface.
🔬 Skin cutaway — impetigo is the SHALLOW one
DEPTH = THE ANSWER The blister forms under the stratum corneum, so its roof is paper-thin. It ruptures almost immediately, and the fluid dries into the honey-colored crust. Because it never reaches the dermis, ordinary impetigo does not scar.
🧠 "Impetigo is a roof problem." The infection is in the roof of the skin, so it peels and crusts instead of swelling and spreading like cellulitis.
📖 Lesion vocabulary — impetigo uses four of these words
Impetigo is a vesicle → pustule → crust story, and the bullous form adds the bulla. Highlighted below.
🧠 Vesicle is small, bulla is big. "B" for BIG bulla.
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PATHO & CAUSES
STEP 1 · WHY IT HAPPENS
Common bacteria + a child's skin + a scratch = the most contagious rash on the ward.
🧠 The one-sentence definition
Impetigo is a very common, highly contagious superficial bacterial skin infection caused by Staphylococcus aureus and/or Group A Streptococcus, affecting mostly infants and young children.
It lives in the top of the epidermis — that is why it crusts rather than swells, and why it usually heals without a scar.
🧠 "Impetigo — infant-igo." The name itself tells you the age group.
⚙️ Mechanism, step by step
Bacteria colonize the nose & skin surface
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A tiny break — scratch, bite, eczema, cut
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Bacteria multiply just under the stratum corneum
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A thin-walled vesicle fills with pus
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It ruptures → oozes → dries into HONEY-COLORED CRUST
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The child scratches → new lesions + other children
🧠 Itch is the engine. Scratching is what seeds the next lesion and the next child — which is why short nails is a real intervention, not a nicety.
⭐ Who gets it & what makes it worse
Age 2–5 years is the classic peak; can occur at any age
Crowding — daycare, school, siblings, sports teams
Warm, humid weather and summer months
Broken skin — eczema, insect bites, chickenpox, scabies, minor trauma
Poor hygiene or limited access to washing facilities
Skin-to-skin contact sports — wrestling, rugby
🧠 "Hot, crowded, scratched." Those three words cover nearly every risk factor.
🚨 How it travels — and the five places you break the chain
🧠 Fomite = an object that carries the bug. Towel, toy, doorknob, wrestling mat. Impetigo spreads by contact, not by air.
🧪 Bug → drug: the rule that runs this whole set
🧠 Bacteria → antibiotic. The only extra decision in impetigo is topical or oral — and that is decided by how much skin is involved.
🔎
CLUES
STEP 2 · WHAT YOU SEE
A child, itchy sores around the nose and mouth, and a crust the color of dried honey.
🍯 The classic picture
🧠 "Golden crust on a small face." If the stem says honey-colored or golden-yellow crust in a child, the answer is impetigo — every time.
👀 Signs & symptoms
Itchy red sores, classically around the nose and mouth; also hands, feet, arms and legs
Sores burst and dry into a stuck-on, honey/golden crust
Lesions at different stages at the same time — new ones keep appearing
Regional lymph nodes may be swollen and tender
Usually little or no fever and the child is otherwise well
Itch, not pain — pain suggests the deeper form (ecthyma) or cellulitis
🧠 Itchy + crusty + a well child = impetigo. Painful + hot + an unwell child = think cellulitis.
🧪 Diagnosis & work-up
Mostly clinical — the appearance is the diagnosis
Swab for culture & sensitivity if it is widespread, recurrent, not responding, or MRSA is suspected
Consider checking for an underlying cause: eczema, scabies, head lice, chickenpox
If PSGN is suspected later: urinalysis (blood + protein), BP, and renal function
🧠 Swab before starting the antibiotic if a swab is being taken at all.
📈 How one sore evolves — and its most contagious moment
🧠 The crust is not the "healed" stage. Students lose marks here: a crusted lesion is still shedding bacteria.
🔬 Three forms — non-bullous vs bullous vs ecthyma
NON-BULLOUS
BULLOUS
ECTHYMA
Depth
Superficial epidermis
Superficial epidermis
Into the dermis
Lesion
Small vesicles → honey crust
Large flaccid bullae > 1 cm
Punched-out ulcer, thick crust
Where
Face, around nose/mouth
Trunk, arms, diaper area
Legs, buttocks
Pain
Itchy
Itchy, may be tender
Painful
Scars?
No
No
Yes
Treatment
Topical, or oral if extensive
Usually oral antibiotic
Oral antibiotic
🧠 "Ecthyma etches." Only the deep one leaves a mark.
🚨 The complication that matters — PSGN
🧠 "Throat → heart. Skin → kidney." Strep throat can lead to rheumatic fever; strep skin infection is the one linked to glomerulonephritis.
🩺
CARE
STEP 3 · WHAT YOU DO
Treat the skin, and stop it reaching the rest of the class.
✅ Stop the spread — the five teaching points
🧠 "School · Soap · Separate · Short nails · Soak." Five S's, in the order you would teach them.
💊 Topical or oral? The decision rule
TOPICAL — for a few localized lesions: mupirocin ointment applied to the lesions after gently removing crust. (Retapamulin and ozenoxacin are alternatives where available.)
ORAL — when it is widespread, bullous, ecthyma, involves multiple household members, or has failed topical therapy: a cephalosporin (cephalexin) or an anti-staph penicillin; clindamycin or TMP-SMX / doxycycline if MRSA is suspected.
🧠 "A few = cream. A lot = pill."
🧽 Crust care — the technique
Gloves on. Standard + contact precautions for draining lesions
Soak with warm soapy water or a saline compress to soften the crust
Gently lift the softened crust — do not scrub or pick at dry crust
Pat dry, then apply the ointment to clean skin — ointment on top of crust does not reach the bacteria
Cover loosely with a non-adherent dressing to stop scratching and shedding
Dispose of dressings as infectious waste; hand hygiene after removing gloves
🧠 Soften, lift, treat, cover. Ointment on crust is wasted ointment.
🗣️ Family teaching — say it exactly like this
"It is very catching — mostly by touch and by shared things."
"Keep them home from school/daycare until the treatment has been in for 24–48 h and the sores are drying up."
"Wash your hands before and after touching the sores or putting on the cream."
"Their own towel, their own bedding — washed separately in hot water."
"Nails short and filed, and try to keep the sores covered."
"Finish the whole course, even when it looks better."
"Come back if the sores spread, get painful, or the child develops fever, puffy eyes, or dark, tea-colored urine."
🧠 The last bullet is the PSGN safety-net. Never end impetigo teaching without it.
❌ Never do these
Never let the child share towels, bedding, washcloths or clothing.
Never scrub or forcibly pick dry crusts — soften them first.
Never send the child back to school just because the sores look drier.
Never apply ointment on top of a thick crust and call it treated.
Never skip hand hygiene between lesion care and any other patient contact.
🧠 Don't share, don't scrub, don't send back early.
📅 What "getting better" looks like
24–48 h: no new lesions appearing; existing sores start drying
3–5 days: crusts loosening and falling away, redness fading
7–10 days: skin healed, usually with no scar (temporary pink or pale patches are normal)
Not improving in 48 h? — reassess: wrong depth (ecthyma), resistant organism, poor adherence, or an untreated underlying condition such as scabies or eczema
🧠 "48 hours is the checkpoint." No improvement by then means something else is going on.
🔀
TELL THEM APART
STEP 4 · THE REAL EXAM SKILL
Crusty and around the mouth is impetigo. Learn what it is NOT.
🗺️ Where each one shows up
🧠 Around the mouth + golden crust = impetigo. Same body, five patterns — distribution answers the question first.
📊 The look-alikes
CONDITION
HOW IT DIFFERS FROM IMPETIGO
Cold sore (HSV-1)
A tight cluster of small vesicles on the lip border, preceded by tingling; recurs in the same spot. Impetigo is more scattered, oozier, and crusts golden.
Cellulitis
Painful, hot, swollen, spreading, often febrile, deep. Impetigo is itchy, superficial and crusty in a well child.
Eczema (atopic dermatitis)
Chronic, dry, itchy, flexural. Watch out: eczema is a common portal of entry, so a child can have both — a suddenly weeping, crusted eczema patch is usually secondarily infected.
Tinea corporis
Ring with a scaly raised edge and a clear center. Fungal — treat with an antifungal, not an antibiotic.
Chickenpox / shingles
Vesicles on a red base; chickenpox is widespread with fever, shingles is one dermatome. Viral — antivirals, not antibiotics.
Scabies
Intense night-time itch, burrows in web spaces, often several family members. Frequently gets secondarily infected with impetigo.
🧠 Golden crust = bacteria. Clustered blisters = virus. A ring = fungus. Night itch in the whole family = mites.
⭐ NCLEX traps
The crusting stage is the MOST contagious, not the least.
School exclusion is tied to treatment started + lesions drying, not to how the sores look alone.
Teaching must include separate laundry in hot water — a frequently-chosen wrong-if-omitted option.
Ointment goes on clean skin after the crust is soaked off.
A painful, punched-out ulcer that scars is ecthyma — it needs an oral antibiotic.
🧠 If the option mentions hot water and separate laundry, look at it hard — it is usually correct.
🧠 One-line contrasts
Impetigo vs cellulitis — crusty & itchy vs hot & painful
Impetigo vs HSV — golden crust vs grouped vesicles that recur in one spot
Impetigo vs tinea — crust vs ring with a clear center
Non-bullous vs bullous — tiny vesicles vs big floppy blisters
Impetigo vs ecthyma — heals clean vs punches into the dermis and scars
🧠 Crust, cluster, ring, ulcer. Four words, four diagnoses.
⚡
QUICK RECALL
SAY IT OUT LOUD
🍯 Honey-colored crustChild · around nose & mouth · itchy.
🚨 Crusting = most contagiousContact + fomites: towels, linen, toys.
💊 Few = cream · Lots = pillMupirocin topically; oral for widespread, bullous or ecthyma.
🏫 5 S'sSchool out · Soap · Separate laundry · Short nails · Soak the crust.
🎯 Cover & check — 8 rapid-fire questions
Q1: Which organisms cause impetigo?
Staphylococcus aureus and Group A Streptococcus (Streptococcus pyogenes) — alone or together.
Q2: Describe the classic lesion and where it appears.
Itchy red sores that burst and dry into a stuck-on, honey-colored (golden) crust, classically around the nose and mouth of a young child; also hands and feet.
Q3: At which stage is impetigo most contagious?
When the vesicles rupture and crust — the oozing/crusting stage. A crusted lesion is still shedding bacteria.
Q4: List the five home/school teaching points.
1. Stay home from school/daycare until treated (about 24–48 hours) and lesions are drying. 2. Wash hands before and after touching the sores. 3. Wash the child's clothes, towels and linen separately in hot water. 4. Keep fingernails short and filed. 5. Gently soak and remove crusts before applying the ointment.
Q5: When would you expect an oral antibiotic rather than a topical one?
Widespread lesions, bullous impetigo, ecthyma, several household members affected, or failure of topical treatment. Topical mupirocin is used for a few localized lesions.
Q6: Which serious complication follows a streptococcal skin infection, and when?
Post-streptococcal glomerulonephritis, typically 1–3 weeks after the skin infection. Teach families to watch for tea/cola-colored urine, puffy eyes, reduced urine output, headache and high blood pressure.
Q7: A child has a painful, punched-out ulcer with a thick crust on the leg. What is it and what changes?
Ecthyma — impetigo that has extended into the dermis. It is painful, needs an oral antibiotic, and it will scar.
Q8: A parent asks whether they can just put the ointment straight over the crust. What do you say?
No — soften the crust first with a warm soapy soak and gently remove it, then apply the ointment to clean skin, or the medicine will not reach the bacteria. Wash hands before and after, and wear gloves if available.