Nursing Field Notes / Skin & Wound · Dermatitis · Pathophysiology Course

🩹 SKIN & WOUND SET NG-051 Skin (foundation) NG-044 Pressure Injuries NG-080 Wound Care NG-116 Frostbite NG-182 Dermatitis NG-225 Psoriasis NG-204 Skin Cancer

Eczema 🌿

Atopic vs Contact Dermatitis — two itchy rashes with completely different stories

NG-182 INTEGUMENTARY · IMMUNE ADHD-friendly visual edition

Both look like an angry, itchy rash. The difference is where it came from. Atopic dermatitis is inside-out: an inherited leaky skin barrier plus an over-reactive immune system, flaring for years in the bends of the joints. Contact dermatitis is outside-in: something touched the skin, and the rash is shaped exactly like whatever touched it.

📄 Simple Nursing original — opens in Drive →

🧬 Atopic = inside-outGenetic · chronic · flares & remits · flexural (elbow & knee creases).

🧪 Contact = outside-inSomething touched it · sharply demarcated to the contact area.

🤝 Atopic TRIADEczema + asthma + allergic rhinitis — ask about all three.

🩹 Moisturise, don't just medicateEmollients are the treatment, not an afterthought. Break the itch–scratch cycle.

🧬

ATOPIC DERMATITIS (ECZEMA)

SIDE A · INSIDE-OUT

A chronic, relapsing, inherited condition — the skin's brick wall is leaky and the immune system is trigger-happy.

🧬 Why atopic skin flares — the barrier cutaway

🧠 Atopic skin is a wall with crumbling mortar. Water leaks out (dry, itchy) and irritants get in (inflamed). That is why moisturiser is not "extra" — it is the treatment.

🤝 The atopic triad — always ask about all three

🌿Atopic dermatitisthe skin

🫁Asthmathe lungs

🤧Allergic rhinitisthe nose

These three travel together and often appear in that order through childhood — the "atopic march." A family history of any of them raises the odds of the others. Serum IgE is often elevated and eosinophils may be raised, but the diagnosis is clinical.

🧠 "Skin, sneeze, wheeze." If a child has bad eczema, ask about night cough, wheeze and a permanently runny nose — you may be the first person to connect them.

⚠️ Cardinal feature: the itch comes first

Atopic dermatitis is "the itch that rashes," not the rash that itches. Pruritus is the defining symptom — it is often worst at night and wrecks sleep for the child and the parents.

Acute flare: erythematous papules and vesicles, weeping serous exudate, crusting.
Subacute: drier, scaly, red plaques.
Chronic: lichenification (thick, leathery skin with exaggerated skin lines), excoriations, pigment change, fissures.
Always: dry skin (xerosis) between flares. The skin is never truly "normal."

🧠 Wet → dry → leather. Acute weeps, subacute scales, chronic thickens. Chart which one you're looking at.

🔬 Acute → subacute → chronic — the same eczema, three faces

🧠 Wet → flaky → leathery. Acute needs drying and calming, subacute needs greasing, chronic needs the scratching stopped.

🗺️ Where it shows up — and it MOVES with age

This single contrast answers the classic exam confusion. Eczema hides in the creases; psoriasis sits on the points. Full detail on the psoriasis side: NG-225 — Psoriasis.

🧠 "Eczema bends, psoriasis extends." Infants are the exception — babies get it on the cheeks and the outsides of the limbs, and the rash migrates into the creases as they grow.

🎯 What sets off a flare

🧼Harsh soapstrips the lipid mortar

🧴Fragranceperfumed products

🧥Wool & syntheticsscratchy fabric

🥵Heat & sweatoverheating, hot showers

🏜️Dry airwinter, indoor heating

🐈Aeroallergensdust mites, dander, pollen

😰Stressa real, documented trigger

🦠Infectionoften S. aureus

Food allergy triggers eczema in a minority of infants and young children — do not restrict a child's diet on your own; that needs an allergy evaluation.

🧠 Hot, dry, scratchy, stressed. Four words that cover most flares — and all four are modifiable.

🚨 Complications — the two you must recognize

Secondary bacterial infection (usually Staphylococcus aureus): honey-colored crusting, pustules, worsening redness and pain, fever. Broken, scratched, weeping skin is an open door.
Eczema herpeticum — herpes simplex spreading across eczematous skin. Clusters of monomorphic "punched-out" vesicles and erosions, rapidly spreading, with fever and a sick-looking child. This is a dermatological emergency — escalate urgently for antiviral treatment.
Sleep deprivation and its knock-on effects on school, work, mood and family function — ask about it and treat it as a real problem.
Skin damage from over-scratching: excoriation, lichenification, fissures, and post-inflammatory pigment change (which is very visible and distressing in darker skin).

🧠 "Honey crust = bacteria. Punched-out vesicles = herpes." The second one gets a phone call, not a wait-and-see.

🧪

CONTACT DERMATITIS

SIDE B · OUTSIDE-IN

Something touched the skin. The rash is a photograph of whatever it was.

🧪 Irritant vs allergic — two different mechanisms

🧠 Irritant = a burn. Allergic = a grudge. An irritant damages anybody's skin the first time; an allergen only reacts in someone the immune system has already met it in — and it takes a day or three to show up.

🔎 The rash is shaped like the culprit

Common culprits to know: irritants — soaps, detergents, solvents, bleach, alcohol gel, frequent hand-washing, saliva (lip-lickers), urine and stool. Allergens — urushiol (poison ivy/oak/sumac), nickel (jewelry, snaps, watch backs, belt buckles), fragrance, preservatives, neomycin, hair dye (PPD) and rubber accelerators in gloves.

🧠 "If the rash has a straight edge, a human-made object made it." Ask: what touches your skin at work, at home, in your hobby, and what is new in the last 3 days?

🌿 Poison ivy — the myths you have to correct

Blister fluid does NOT spread the rash. New patches appear later because thinner skin reacts later, or because there was more urushiol there.
The rash is not contagious person-to-person. But urushiol on clothing, boots, tools, gloves and pet fur absolutely re-exposes you — wash all of it.
Wash the skin with soap and cool water as soon as possible after exposure — ideally within minutes. Once it is bound, washing no longer prevents the reaction.
The rash appears hours to a few days after exposure and typically lasts 1–3 weeks.
Never burn poison ivy — inhaling the smoke can cause severe airway reactions.
"Leaves of three, let it be" — and cool compresses, calamine, topical steroids; extensive or facial involvement often needs systemic corticosteroids by prescription.

🧠 The oil is the enemy, not the blister. Wash the person, wash the clothes, wash the dog.

⚠️ Latex — know which reaction you are being asked about

Irritant contact dermatitis — dry, cracked hands from glove occlusion, powder and hand-washing. Not an allergy at all.
Type IV allergic contact dermatitis — delayed, itchy, eczematous, usually to rubber accelerator chemicals; appears 24–72 h after wearing gloves.
Type I latex allergy — IgE-mediated, immediate: urticaria, angiedema, wheeze, anaphylaxis. This is the life-threatening one.
Cross-reactive foods ("latex–fruit syndrome"): banana, avocado, kiwi, chestnut. Ask about them.
High-risk groups: healthcare workers, and patients with spina bifida or multiple surgeries.

🧠 Delayed & itchy = Type IV rash. Immediate & wheezy = Type I emergency. Same word "latex," completely different answer.

⚖️

TELL THEM APART

STEP 3 · COMPARE

The table the exam question is written from.

⭐ Atopic vs Irritant contact vs Allergic contact

Feature	Atopic dermatitis	Irritant contact	Allergic contact
Cause	Inside-out: inherited barrier defect + over-reactive immune response	Outside-in: direct chemical/physical damage to the barrier	Outside-in: Type IV delayed hypersensitivity (T-cell mediated)
Immune memory?	Yes — chronic immune dysregulation, ↑ IgE	No — anyone gets it with enough exposure	Yes — needs prior sensitization
First exposure?	N/A — lifelong tendency	Reacts on the first exposure	No reaction the first time; reacts on re-exposure
Timing	Chronic, flares and remits over years	Minutes to hours; dose-dependent	12–72 hours after contact (delayed)
Main symptom	Intense itch, worse at night	Burning, stinging > itch	Intense itch
Where	Flexural — elbow & knee creases, neck, wrists (infants: cheeks + extensor)	Exactly where the substance touched; hands are classic	Where it touched, but may spread a little beyond
Borders	Ill-defined, blends into dry skin	Sharply demarcated, geometric	Sharp-ish, often linear or object-shaped
Look	Red plaques, weeping serous exudate in flares, lichenification + excoriations when chronic; always dry	Dry, cracked, glazed, fissured; less vesicle formation	Vesicles, weeping, edema, marked redness
Associated with	Asthma + allergic rhinitis (atopic triad), family history	Occupation, wet work, frequent handwashing	A specific allergen — nickel, urushiol, fragrance, neomycin
Test	Clinical; ↑ IgE/eosinophils may support	Clinical + exposure history	Patch testing (read at 48 h and again at 72–96 h)
Core treatment	Emollients + topical anti-inflammatories + trigger control; long-term	Remove the irritant, barrier protection, emollients	Identify and avoid the allergen; topical (or systemic if severe) steroids

🧠 Three questions sort them: (1) Is it in the creases and chronic? → atopic. (2) Did it show up the same day, shaped like an object, burning? → irritant. (3) Did it show up 1–3 days later, itching furiously, in the shape of something? → allergic.

⚖️ Eczema vs psoriasis — the other classic mix-up

Eczema (atopic dermatitis)	Psoriasis
FLEXURAL — inside the elbows and behind the knees	EXTENSOR — outside of elbows, front of knees, scalp, lower back
Itch is severe and the dominant symptom	Itch is variable; may burn or sting instead
Ill-defined edges; weeping and crusting in flares	Sharply demarcated, thick plaques with silvery-white scale
Lichenification, excoriations, dry skin between flares	Scraping the scale can cause pinpoint bleeding (Auspitz sign); Koebner phenomenon — new plaques at sites of injury
Usually starts in infancy/early childhood; may improve with age	Peaks in young adulthood and again later; lifelong
Associated with asthma and allergic rhinitis	Associated with psoriatic arthritis, nail pitting/onycholysis, metabolic syndrome
Epidermal turnover is normal-ish; the barrier is the problem	Keratinocyte turnover is massively accelerated — days instead of ~28

Full detail on the psoriasis side: NG-225 — Psoriasis. The keratinocyte escalator that psoriasis speeds up is drawn on NG-051 — Skin.

🧠 "Eczema bends and weeps. Psoriasis extends and flakes." Then check the nails — pitting points to psoriasis.

🔁 The itch–scratch cycle — why it never just settles

🧠 Scratching feels like treatment and behaves like fuel. Every intervention on the next section exists to break this loop.

🩺

CARE & TEACH

STEP 4 · MANAGE

Most of this is teaching — and most of the teaching is about moisturiser.

✅ Atopic dermatitis — the daily routine that actually works

Bathe smart
Short (5–10 min), lukewarm bath or shower once daily. Fragrance-free, non-soap cleanser — no bubble bath, no scrubbing, no washcloths on inflamed skin. Pat dry, don't rub.

▼

"Soak and seal"
Apply emollient within about 3 minutes of getting out, while the skin is still damp. Thick ointments and creams beat lotions. Apply liberally, at least twice a day and every time after washing hands — even when the skin looks fine.

▼

Treat the inflammation
Topical corticosteroids to active areas, at the lowest effective potency for the shortest effective time. Use low potency on the face, eyelids, axillae and groin; higher potency is reserved for thick skin like palms and soles. Apply the steroid first, then the emollient over the top (or as directed).

▼

Steroid-sparing options
Topical calcineurin inhibitors (tacrolimus, pimecrolimus) for delicate areas and long-term control — expect transient burning/stinging on application and advise sun protection. Severe disease may be escalated to phototherapy or a biologic such as dupilumab. Prescriber-directed.

▼

Control the itch
Cool compresses, cotton clothing, nails cut short and filed smooth, cotton mittens/sleepsuits for infants at night, keep the bedroom cool. Sedating antihistamines are used mainly to help sleep — they do not treat the eczema itself. Wet-wrap therapy for severe flares, per protocol.

▼

Remove triggers
Fragrance-free detergent, double-rinse laundry, no fabric softener; cotton not wool; humidify dry indoor air; manage dust mites; manage stress; avoid overheating.

🧠 "Soak and seal, then steal the steroid back." Emollients every single day; steroids only for the flare, and the weakest one that works.

💊 Topical steroid potency by body region — thin skin needs weak steroid

🧠 "Weak where the skin is thin." Face, eyelids, armpits and groin get the gentlest preparation; palms and soles can take the strongest.

✅ Contact dermatitis — the treatment is detective work

Identify and remove the agent. Nothing else works if the exposure continues. Take a full history: occupation, hobbies, new products, jewelry, cosmetics, topical medicines, plants, gloves.
Wash the area with mild soap and cool water as soon as possible after exposure; wash contaminated clothing, tools and pets.
Cool compresses and colloidal oatmeal baths for weeping, itchy skin; calamine for symptom relief.
Topical corticosteroids for localized disease; systemic corticosteroids for severe or widespread reactions (classically extensive poison ivy or facial involvement) — prescriber-directed, usually tapered.
Emollients and barrier creams once the acute weeping settles, especially for irritant hand dermatitis.
Protect at work — appropriate gloves (cotton liners under occlusive gloves), limit wet work, moisturise after every wash.
Patch testing if allergic contact dermatitis is suspected and the culprit isn't obvious.

🧠 "Find it, remove it, wash it, calm it." In that order — steroids on top of ongoing exposure just chase the rash.

👨‍👩‍👧 Teach the family — the sentences that land

"This is not contagious and it is not your fault." Say it out loud, especially to parents and to school-age children.
"Moisturiser is medicine." Every day, forever — not only when it flares.
"Use the steroid properly and you'll use less of it." Under-treating a flare from steroid fear leads to longer, worse flares. Use as prescribed, on the areas prescribed.
"Short nails, cotton clothes, cool room."
Call for: honey-colored crusting, pus, fever, rapidly spreading painful blisters/punched-out sores (possible eczema herpeticum), or a flare that doesn't respond to the usual plan.
Acknowledge the sleep loss, school/work impact and body-image distress — this is a chronic disease, and support matters.

🧠 One line for the fridge door: "Bathe short, seal in 3 minutes, steroid for the flare, call for crusts or fever."

🗺️ Where this page sits in the set

NG-051 — Skin: the barrier, Langerhans cells and the lesion words (vesicle, plaque, lichenification, excoriation) used all over this page.
NG-225 — Psoriasis: the extensor-surface, silvery-scale counterpart. Learn the two together or you will mix them up.
NG-080 — Wound Care: for excoriated, weeping or secondarily infected skin.

🧠 Creases + itch + asthma = eczema. Points + silver scale + nails = psoriasis. Straight edges = contact.

⚡

QUICK RECALL

SAY IT OUT LOUD

🧬 Eczema bendsFlexural creases · chronic · intensely itchy · atopic triad.

🧪 Contact copies the objectSharp, geometric borders in the shape of what touched it.

⏱️ Irritant fast · allergic slowIrritant = same day, burns. Allergic = 12–72 h later, itches (Type IV).

🚨 Punched-out vesicles + feverEczema herpeticum — escalate now.

🎯 Cover & check — 9 rapid-fire questions

Q1: Name the atopic triad.

Atopic dermatitis (eczema), asthma, and allergic rhinitis. They often appear in that order through childhood — the "atopic march."

Q2: Where is atopic dermatitis found in an infant, and where in an older child?

Infants: cheeks, scalp, trunk and the extensor surfaces of the limbs, typically sparing the diaper area. Older children and adults: the flexural creases — antecubital and popliteal fossae — plus neck, wrists and ankles.

Q3: A rash appeared 2 days after gardening, in itchy linear streaks with vesicles on the forearm. What is it and what type of reaction?

Allergic contact dermatitis to urushiol (poison ivy/oak/sumac) — a Type IV delayed hypersensitivity reaction, appearing 12 to 72 hours after exposure. The linear streaks come from brushing past the plant.

Q4: Does blister fluid spread poison ivy?

No. Blister fluid does not contain urushiol and does not spread the rash. New areas appear later because thinner skin reacts more slowly or received more oil. However, urushiol remaining on clothing, tools, shoes and pet fur will re-expose the person, so all of it should be washed.

Q5: How do irritant and allergic contact dermatitis differ on first exposure?

Irritant contact dermatitis can occur on the very first exposure in anyone — it is direct chemical damage with no immune memory. Allergic contact dermatitis requires prior sensitization, so the first exposure produces no rash; the reaction comes on re-exposure.

Q6: What is the single most important daily treatment for atopic dermatitis?

Emollients. Short lukewarm baths with a fragrance-free non-soap cleanser, then a thick moisturiser applied within about three minutes of getting out — "soak and seal" — applied at least twice a day, every day, including when the skin looks clear.

Q7: Why use low-potency topical steroid on the face and higher potency on the palms?

Because skin thickness and absorption differ. Thin skin (face, eyelids, axillae, groin) absorbs far more and is prone to atrophy, striae and telangiectasia, so it needs the lowest effective potency. Thick skin like palms and soles absorbs poorly and may need a stronger preparation.

Q8: A child with known eczema now has clusters of uniform punched-out vesicles and erosions spreading rapidly, with a fever. What is your concern?

Eczema herpeticum — herpes simplex superinfection of eczematous skin. It is a dermatological emergency requiring urgent escalation for antiviral treatment.

Q9: How do you distinguish eczema from psoriasis at a glance?

Distribution and scale. Eczema is flexural (inside the elbows, behind the knees), ill-defined, intensely itchy, and weeps or lichenifies. Psoriasis is extensor (outside the elbows, front of the knees, scalp, lower back), sharply demarcated, with thick silvery-white scale, and is associated with nail pitting and psoriatic arthritis. "Eczema bends, psoriasis extends."