Dermatology or Rash History Taking | OSCE Guide

Learn a structured rash and dermatology history for OSCEs, including lesion description, distribution, triggers, red flags, common dermatological patterns and appropriate examination and investigation steps for PA students.

1. 🧼 Opening the Consultation

  • Wash or sanitise hands
  • Introduce yourself: "Hi, my name is (Name), one of the physician associates"
  • Confirm the patient's full name and date of birth
  • Gain consent: "Would it be okay if I asked you some questions about the skin problem you've been experiencing?"
  • Ask whether the patient is comfortable showing the affected area and maintain dignity throughout the consultation
  • Establish whether the patient appears acutely unwell or has a rapidly spreading, painful or blistering rash

2. ❓ Presenting Complaint

  • Begin openly:
    • "What brought you in today?"
    • "Can you tell me about the problem you've noticed with your skin?"
  • Clarify whether the patient is describing:
    • A widespread rash
    • A localised rash
    • A single skin lesion
    • An ulcer or wound
    • Blisters
    • Itching without an obvious rash
    • A change in an existing mole or lesion
  • If the patient says… You should consider…
    "It's really itchy and worse at night" Scabies, eczema or another pruritic condition
    "It started after I used a new cream" Contact dermatitis
    "The patches are dry and itchy" Eczema or dermatitis
    "I've got thick scaly patches on my elbows and knees" Psoriasis
    "It's a ring-shaped itchy patch that's getting bigger" Dermatophyte infection such as tinea corporis
    "It burns and there are blisters on one side" Herpes zoster
    "It's hot, painful and spreading" Cellulitis or another acute skin infection
    "The rash appeared after starting a new medicine" Drug eruption – assess carefully for severe cutaneous reactions
    "This mole has changed recently" Assess for possible melanoma or another skin malignancy

3. 🩺 History of Presenting Complaint

  • Onset: "When did you first notice the rash or skin lesion?"

    Sudden onset may suggest urticaria, infection, an allergic reaction or a drug reaction. Gradual changes are more typical of chronic inflammatory or neoplastic conditions.

  • First location: "Where did it first appear?"
  • Spread: "Has it stayed in the same place or spread anywhere else?"

    The way a rash spreads can be diagnostically useful. Ask which area appeared first rather than only where the rash is now.

  • Progression: "How has it changed since you first noticed it?"
    • Getting larger?
    • More lesions appearing?
    • Changing colour?
    • Becoming raised?
    • Blistering?
    • Crusting or weeping?
    • Bleeding?
    • Ulcerating?
  • Itch: "Is it itchy?"
    • How severe?
    • Worse at night?
    • Disturbing sleep?
    • Anyone else at home itching?

    Severe nocturnal itch affecting household contacts should raise suspicion of scabies.

  • Pain: "Is the rash painful, sore, burning or tender?"

    Pain can be particularly important. Painful blistering or skin detachment may represent a serious dermatological emergency.

  • Discharge: "Has there been any fluid, pus, bleeding or weeping from the area?"
  • Previous episodes: "Have you ever had anything like this before?"

    Recurrent flexural eczema, psoriasis, herpes simplex, urticaria and hidradenitis may have recognisable previous episodes.

  • Treatment already tried: "Have you tried anything on it so far?"
    • Moisturisers or emollients?
    • Topical corticosteroids?
    • Antifungal treatment?
    • Antibiotics?
    • Antihistamines?
    • Over-the-counter creams?

    Ask whether treatment helped, worsened the rash or changed its appearance.

4. 🔍 Describe the Rash or Lesion

  • Location: "Which areas of your body are affected?"
  • Distribution:
    • Localised or widespread?
    • Symmetrical or asymmetrical?
    • Flexural or extensor surfaces?
    • Exposed or covered areas?
    • Dermatomal?
    • Palms or soles?
    • Scalp?
    • Face?
    • Groin?
  • Mucosal involvement: "Have you noticed any sores, ulcers or blisters inside your mouth, around your eyes or around the genital area?"

    Mucosal involvement is important in conditions including Stevens–Johnson syndrome, toxic epidermal necrolysis, erythema multiforme and some autoimmune blistering disorders.

  • Appearance: ask the patient how it has looked over time.
    • Flat or raised?
    • Red, purple, brown or darker than surrounding skin?
    • Scaly?
    • Crusted?
    • Blistering?
    • Pustular?
    • Ring-shaped?
Appearance or distribution You should consider…
Dry itchy flexural patches Atopic eczema
Well-defined plaques with scale on extensor surfaces Psoriasis
Annular scaly lesion with central clearing Tinea corporis
Transient raised itchy wheals Urticaria
Grouped painful vesicles in a dermatomal distribution Herpes zoster
Honey-coloured crusted lesions Impetigo
Hot, swollen, painful expanding area of skin Cellulitis or erysipelas
Burrows or papules around finger webs, wrists or waist with intense nocturnal itch Scabies
Recurrent painful nodules or abscesses in axillae or groin Hidradenitis suppurativa
Non-blanching petechiae or purpura with systemic illness Meningococcal disease or another serious cause of purpura

5. 🧴 Triggers & Exposures

  • New skin products:
    • Soap
    • Shower gel
    • Moisturiser
    • Perfume
    • Cosmetics
    • Hair products
  • Household products:
    • Detergents
    • Cleaning chemicals
    • Latex or gloves
  • Occupational exposure: "Does your work involve chemicals, frequent handwashing, gloves, oils, dust or other irritants?"
  • Sun exposure:
    • Recent sunburn?
    • Outdoor occupation?
    • Sunbeds?
    • Does sunlight worsen the rash?
  • Contacts: "Has anyone at home, work or school developed a similar rash or itching?"
  • Animals: pets or animal exposure
  • Travel: recent travel where clinically relevant
  • Insect bites: ask about recent bites, outdoor activities or new accommodation

6. 🌡️ Associated Symptoms

  • Systemic illness:
    • Fever
    • Chills or rigors
    • Feeling significantly unwell
    • Reduced oral intake
    • Unexplained weight loss
  • Allergic symptoms:
    • Lip or tongue swelling
    • Throat tightness
    • Difficulty swallowing
    • Wheeze
    • Breathlessness
    • Dizziness or collapse

    Urticaria or skin changes accompanied by airway, breathing or circulation problems should raise concern for anaphylaxis.

  • Joint symptoms:
    • Joint pain
    • Joint swelling
    • Morning stiffness

    Joint symptoms may be relevant in psoriasis, connective tissue disease and systemic inflammatory conditions.

  • Eye symptoms:
    • Eye pain
    • Redness
    • Photophobia
    • Visual disturbance
  • Oral symptoms: ulcers, erosions, soreness or difficulty eating
  • Hair and nails:
    • Hair loss
    • Nail pitting
    • Nail thickening or discolouration
    • Nail separation

7. 🚩 Dermatology Red Flag Screen

Ask specifically about:
  • Rapidly spreading non-blanching petechial or purpuric rash
  • Fever or systemic illness with a non-blanching rash
  • Airway swelling, wheeze, breathing difficulty, dizziness or collapse associated with a rash
  • Widespread blistering or skin peeling
  • Painful rash with oral, eye or genital mucosal involvement
  • Recent introduction of a medication before a painful widespread rash
  • Rapidly spreading painful erythema with significant systemic illness
  • Pain significantly greater than expected from the appearance of the skin
  • Rash involving the eye or surrounding structures
  • Severe infection in an immunosuppressed patient
  • New or rapidly changing pigmented lesion
  • Non-healing, ulcerating or persistently bleeding skin lesion
🚨 Think dermatological emergency
  • Non-blanching rash + systemic illness: consider meningococcal disease and arrange emergency assessment
  • Rash + airway, breathing or circulation compromise: consider anaphylaxis
  • Painful widespread rash + mucosal erosions + blistering or skin detachment: consider Stevens–Johnson syndrome or toxic epidermal necrolysis
  • Rapidly progressive painful skin infection + severe systemic illness: consider a serious soft tissue infection

8. 🧠 Recognising Common Dermatology Patterns

If the patient describes… You should consider…
Dry, itchy, recurrent rash particularly affecting flexures Atopic eczema
Rash appearing after contact with a particular cosmetic, chemical or irritant Contact dermatitis
Well-demarcated scaly plaques affecting elbows, knees or scalp Psoriasis
Facial flushing, persistent central facial redness or papules Rosacea
Comedones, papules or pustules affecting the face, chest or back Acne vulgaris
Annular itchy scaly lesions with an active edge Dermatophyte infection
Transient itchy wheals appearing and disappearing within hours Urticaria
Severe itch at night with affected household contacts Scabies
Pain or burning followed by unilateral grouped vesicles in a dermatome Herpes zoster
Hot, painful expanding skin with swelling and systemic symptoms Cellulitis
Recurrent painful nodules, abscesses or sinus tracts in axillae or groin Hidradenitis suppurativa
Single larger patch followed days later by multiple smaller oval lesions on the trunk Pityriasis rosea
New widespread rash soon after starting medication Drug eruption

9. 🔎 Changing Mole or Skin Lesion

  • Change in size: "Has the lesion become larger?"
  • Change in shape: "Has the shape or border changed?"
  • Change in colour: "Have you noticed new colours or uneven pigmentation?"
  • Symptoms:
    • Itching
    • Pain
    • Change in sensation
    • Inflammation
  • Surface changes:
    • Bleeding
    • Oozing
    • Crusting
    • Ulceration
  • Duration: "How long has the lesion been present, and when did you first notice it changing?"
  • Previous skin cancer: melanoma, squamous cell carcinoma or basal cell carcinoma
  • Sun exposure: previous sunburn, sunbeds and occupational or recreational exposure
Lesion feature Why it matters
Change in size Major suspicious feature for melanoma
Irregular shape Major suspicious feature for melanoma
Irregular colour Major suspicious feature for melanoma
Inflammation, oozing or change in sensation Additional concerning features
Ulcerated lesion with a raised rolled edge or pearly appearance Consider basal cell carcinoma
Persistent enlarging, crusted, keratotic or ulcerated lesion Consider squamous cell carcinoma

10. 📋 Past Medical History

  • Eczema or dermatitis
  • Psoriasis
  • Acne
  • Rosacea
  • Previous fungal infections
  • Previous herpes simplex or shingles
  • Previous cellulitis
  • Diabetes
  • Peripheral vascular disease
  • Venous insufficiency or lymphoedema
  • Autoimmune disease
  • Previous skin cancer
  • Other malignancy
  • Immunosuppression
  • HIV where clinically relevant

11. 💊 Drug History & Allergies

  • "What medications are you currently taking, including anything you've bought yourself?"
  • New medication: "Have you started any new medication recently or had a dose changed?"

    Establish the exact timing between starting the medication and the onset of the rash. Drug eruptions can appear days or weeks after exposure.

  • Ask about:
    • Antibiotics
    • NSAIDs
    • Anticonvulsants
    • Allopurinol
    • Immunosuppressants
    • Biological therapies
    • Topical treatments
    • Herbal or complementary products
  • Drug allergies: establish the medication, reaction and timing

12. 👨‍👩‍👧‍👦 Family History

  • Eczema
  • Asthma or allergic conditions
  • Psoriasis
  • Autoimmune conditions
  • Melanoma or other skin cancer
  • Similar skin problems in family members

13. 🏠 Social History

  • Occupation: consider occupational irritants or allergens
  • Smoking: current or previous
  • Alcohol: amount and frequency
  • Sun exposure: outdoor work, holidays, sunburn and sunbed use
  • Skin care: soaps, moisturisers, cosmetics and fragrances
  • Household contacts: ask whether anyone else has a similar rash or itching
  • Sexual history: consider where the rash involves the genital area or an STI is possible
  • Impact on life:
    • Sleep
    • Work or study
    • Relationships
    • Exercise
    • Self-confidence
    • Daily activities

14. 💬 ICE – Ideas, Concerns & Expectations

  • "Do you have any thoughts about what might be causing the skin problem?"
  • "Is there anything in particular you're worried this could be?"
  • "What were you hoping we could help you with today?"

15. 🧾 Summarise & Explain Next Steps

"So, you've had a (description) rash affecting (site) for around (duration). It began (onset) and has since (progression). It is associated with (itch/pain/discharge or other symptoms), and you have/have not noticed any concerning symptoms such as fever, mucosal involvement or blistering. Relevant triggers include (exposure), and your background includes (relevant PMH or medication history)".

"I'd like to examine the affected skin and check whether there are any other areas involved. Depending on what it looks like, we can then decide whether any tests, treatment or referral are needed".

🔎 Targeted next steps
  • Inspect the lesion or rash carefully
  • Document site and distribution
  • Describe morphology, colour, border and surface
  • Check whether lesions blanch where clinically relevant
  • Assess warmth, tenderness and swelling
  • Look for secondary infection
  • Inspect nails, scalp and mucosal surfaces where appropriate
  • Check regional lymph nodes where relevant
  • Assess the remainder of the skin if a widespread condition is suspected
  • Remember erythema may be less visually obvious on darker skin tones
  • Consider clinical photography where appropriate and with consent
🚨 Urgent escalation

A rapidly spreading non-blanching rash with systemic illness, suspected anaphylaxis, widespread painful blistering or skin detachment, significant mucosal involvement, severe rapidly progressive skin infection or another dermatological emergency requires urgent assessment.

16. 🔬 Investigations – Think Targeted

  • Many common dermatological conditions: can be diagnosed clinically without routine blood tests.
  • Suspected fungal infection: consider skin, hair or nail sampling for microscopy and culture where confirmation is needed.
  • Suspected bacterial infection: microbiological swabs may be useful where there is purulent discharge, broken skin or another specific indication.
  • Cellulitis: diagnosis is usually clinical. Consider investigations if the patient is systemically unwell or an alternative diagnosis or unusual organism is suspected.
  • Suspected drug eruption: establish the medication timeline carefully and investigate organ involvement if a severe drug reaction is suspected.
  • Persistent unexplained pruritus: consider targeted blood tests for possible underlying systemic causes depending on the history and examination.
  • Suspicious pigmented lesion: assess using appropriate skin cancer criteria and refer through the suspected cancer pathway where indicated.
  • Possible melanoma or squamous cell carcinoma: follow the appropriate suspected cancer pathway.
  • Skin biopsy: may be required where the diagnosis remains uncertain or malignancy, inflammatory disease or an autoimmune blistering disorder is suspected.

🎓 Present Back to Examiner (PA Format)

"This is a (age)-year-old (man/woman) presenting with a (duration) history of a (description) rash affecting the (distribution). It began on the (initial site) and has since (progression). The rash is associated with (itch/pain or other symptoms), with no (important red flags). Relevant exposures include (exposure), and background history includes (relevant PMH or medication history). My leading differential is (diagnosis), with (diagnosis 2) and (diagnosis 3) also considered. I would perform a full skin examination focusing on morphology and distribution, assess for systemic involvement and arrange targeted investigations or referral depending on the findings".

📚 Key References

  • NICE NG12 - Suspected cancer: recognition and referral.
  • NICE NG240 - Bacterial meningitis and meningococcal disease: recognition, diagnosis and management.
  • NICE CG183 - Drug allergy: diagnosis and management.
  • NICE NG141 - Cellulitis and erysipelas: antimicrobial prescribing.
  • NICE NG190 - Secondary bacterial infection of eczema and other common skin conditions: antimicrobial prescribing.