Skin Rash OSCE - Eczema Flare

Case Overview

• Age/Sex: 18-year-old female
• Occupation: University student (undergraduate)
• Setting: Primary care clinic walk-in
• Chief complaint: "Rash on my skin"

Patient Script

Who I Am

I'm an 18-year-old university student, living in halls and juggling exams at the moment.

What Brings Me In

I've had a really itchy rash on my arms and behind my knees for the last couple of weeks and it's getting worse, so I thought I should get it checked.

My Story

About two weeks ago I noticed an area of red, itchy skin in the crook of my elbow. Over the next few days it spread to my other elbow and the backs of my knees. It's very itchy, especially at night, and I have been scratching a lot so some bits look sore. I last week started revision for exams and have been really stressed — the itching seems worse when I'm anxious. I also tried a new laundry detergent about 1 week ago, which made me wonder if it was an allergy. I used an over-the-counter hydrocortisone cream from a friend once and it helped a bit for a day, but now that it's spread the cream doesn't seem to do much.

I had a slight sore throat and felt a bit warm for a day three days ago, but no high fever. I had a small insect bite on my forearm three weeks ago but that healed. I am not pregnant. I sleep badly because of the itching and it's affecting my studying.

My Medical Background

• Past medical history: eczema as a child (used to have dry skin and patches when I was little), otherwise well
• Medications: combined oral contraceptive (started 3 months ago), paracetamol as needed
• Allergies: none known
• Social: lives in university halls, non-smoker, drinks alcohol occasionally, no recreational drugs, has a pet cat at home but cat is at parents' house
• Family: mother has hay fever; father has asthma

What I Think & Worry About

• I think it might be an allergy to the new detergent or something in halls.
• I'm worried it could get infected or that I'll miss exams because I can't sleep.
• I'm anxious it might be something serious or contagious and I'll have to move out of halls.

If You Ask Me About Other Symptoms...

• Itch: "It's terrible at night — wakes me up sometimes."
• Pain: "Mostly not painful, just sore where I scratch a lot."
• Fever/systemic: "Only felt a bit warm for a day, no real fever, no chills."
• Breathing/wheeze: "I get a bit wheezy sometimes when I have hay fever, but not now."
• New products/contacts: "I did start a new detergent a week ago and used a scented shower gel a couple of times."
• Recent travel: "No, I haven't been away recently."
• Previous skin problems: "I had eczema when I was younger but I didn't have it for years — just dry skin sometimes."
• Treatments tried: "Just that hydrocortisone cream from a friend once."

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Clinical Summary

Examination

• General: alert, comfortable at rest, appears mildly anxious
• Vitals: HR 82 bpm, BP 110/68 mmHg, RR 14/min, Temp 37.2°C, SpO2 99% on air
• Skin: bilateral erythematous, scaly patches with areas of lichenification and superficial excoriation in the antecubital fossae and popliteal fossae; some serous crusting at excoriated sites but no frank pus
• Distribution: predominantly flexural (elbow creases, behind knees), also mild involvement of wrists and neck
• Lymph nodes: small, mobile, non-tender cervical and axillary nodes
• No mucosal lesions, no target lesions, no burrows in finger webs

Investigations

• CBC: WBC 7.5 x10^9/L (neutrophils 5.2, lymphocytes 1.8, eosinophils 0.5 x10^9/L [~6.7%]) (interpretation: normal WBC with mild eosinophilia)
• Serum total IgE: 280 IU/mL (reference <100) (interpretation: elevated, supportive of atopy)
• Skin swab from crusted area: Staphylococcus aureus grown (MSSA) (interpretation: colonization/possible secondary infection)
• Pregnancy test (urine): negative (interpretation: not pregnant)

Diagnosis

• Primary: Atopic dermatitis (eczema) — flare

  • Evidence: history of childhood eczema, typical flexural distribution (antecubital/popliteal fossae), intense pruritus especially at night, lichenification and excoriation on exam, elevated IgE, family history of atopy.

• Differentials:

  • Allergic/contact dermatitis — possible given new detergent (red herring): usually more localized to contact sites and can be acute; less likely given long-standing atopic history and flexural distribution.
  • Scabies — intense nocturnal itch could fit, but absence of burrows in webs and typical distribution less suggestive.
  • Secondary bacterial infection of eczema — supported by Staph aureus on swab and crusting; clinical signs not strongly in favor of deep infection (no high fever, no spreading cellulitis).
  • Nummular eczema or psoriasis — distribution and history favor atopic eczema over these.

Management

• Immediate symptomatic care:
  • Start liberal emollient therapy: apply emollient ointment or cream frequently (at least twice daily and after washing); use as soap substitute.
  • Topical corticosteroids for flare: prescribe a moderate-potency steroid for affected body flexures for short course (e.g., betamethasone valerate 0.1% once or twice daily for up to 1–2 weeks) but use low-potency (hydrocortisone 1%) for sensitive areas (face/neck) and explain correct thin application and step-down approach.
  • Consider a topical calcineurin inhibitor (e.g., tacrolimus) for facial or steroid-sensitive areas if needed or if patient concerned about steroid side-effects — refer to local guidelines.
  • Oral sedating antihistamine at night for itch and sleep disturbance (e.g., cetirizine or chlorphenamine) if symptomatic.
• Address secondary infection:
  • If clinical signs of bacterial infection (increasing pain, spreading erythema, purulent discharge) start oral antibiotics targeting S. aureus (e.g., flucloxacillin) — in this case, discuss with patient and consider a short course since swab grew MSSA and there is crusting, but no systemic features.
• Trigger and skincare advice:
  • Advise to stop using the new detergent and scented products until rash settles; avoid hot showers, wear cotton, avoid scratching, keep nails short.
  • Stress can exacerbate eczema — discuss coping strategies and university support services.
• Safety-netting and follow-up:
  • Arrange GP/clinic follow-up in 1–2 weeks to review response; earlier if worsening, spreading redness, fever, or increasing pain suggestive of infection.
  • Consider dermatology referral if severe, recurrent flares, steroid-refractory, or diagnostic uncertainty; consider patch testing if contact allergy suspected after control of inflammation.

Key Learning Points

• Atopic dermatitis commonly presents with intensely pruritic, flexural, lichenified lesions and is often associated with personal or family history of atopy; emollients are the cornerstone of management.

• Use topical corticosteroids of appropriate potency for flares, educate about correct application and step-down therapy, and consider topical calcineurin inhibitors for steroid-sensitive areas.

• Secondary bacterial colonization or infection (commonly Staphylococcus aureus) can complicate eczema; treat clinically significant infection with appropriate antibiotics and urgent review if systemic signs develop.