Skin Rash OSCE - Shingles

Case Overview

• Age/Sex: 72-year-old female
• Occupation: Retired primary school teacher
• Setting: Primary care / urgent clinic
• Chief complaint: "Rash on my skin"

Patient Script

Who I Am

I am 72, retired, live at home with my husband and I like gardening.

What Brings Me In

I have a painful rash on the left side of my chest and ribs that started a few days ago and it’s getting worse.

My Story

About 5 days ago I noticed a strange tingling and burning feeling along the left side of my chest and flank. It felt like a burning/stinging pain and was bothering me but there wasn’t anything to see. Then 3 days ago small red bumps appeared and yesterday some of them turned into clear blisters. Today several blisters look like they are starting to crust over. The pain is constant and sharp at times — about 6 out of 10, worse when I move or when my clothes rub on it. The rash is all on the left side and hasn’t crossed the middle of my body. I haven’t had anything exactly like this before.

I also had a urinary tract infection treated with antibiotics (ciprofloxacin) about 2 weeks ago, and I had my flu shot about a month ago. I’ve been doing a lot of gardening recently and thought at first it might be an insect bite or that I reacted to a new laundry soap I started using last week.

My Medical Background

• Past medical history: Type 2 diabetes (diagnosed 15 years ago), hypertension, chronic kidney disease stage 3, prior myocardial infarction 8 years ago
• Medications: Metformin 1g twice daily, insulin glargine 20 units nightly, lisinopril 10 mg daily, atorvastatin 20 mg nocte, aspirin 75 mg daily, inhaled salbutamol PRN
• Allergies: Penicillin — caused a rash when I was younger
• Social: Lives with husband, independent with activities, non-smoker, drinks a glass of wine occasionally, active gardener
• Family: Mother had diabetes, father died of stroke

What I Think & Worry About

• I think it might be an allergic reaction to the new soap or something I got while gardening.
• I’m worried it could be something serious, like skin cancer or infection, or that it might spread to my husband or get worse.
• I’m worried about the pain sticking around and stopping me from looking after myself.

If You Ask Me About Other Symptoms...

• Pain: The pain started a couple of days before the rash and is burning and very sensitive to touch.
• Fever/systemic: I haven’t had a high fever but I felt a bit off and sweaty two days ago.
• Vision/eyes: No eye redness, pain, or vision change.
• Numbness/weakness: No weakness in my arms or legs, but the skin in the rash area feels extra sensitive and a bit numb in places.
• New medications: Only the ciprofloxacin 2 weeks ago and the new laundry soap last week.
• Past similar problems: I had chickenpox as a child but never this rash before.
• Wound/injury: No recent cuts or bites there except maybe a few tiny mosquito bites when gardening.

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Clinical Summary

Examination

• General: Alert, comfortable at rest but distressed by localized pain
• Vitals: Temperature 37.8°C, BP 142/84 mmHg, HR 88 bpm, RR 16/min, SpO2 97% on air
• Skin: Grouped vesicular lesions on an erythematous base distributed in a unilateral, contiguous band over the left anterolateral chest and T4–T6 dermatome region; some vesicles intact, some cloudy, a few beginning to crust; lesions do not cross midline
• Lymph nodes: Small, tender left axillary lymph nodes
• Neuro: Hyperesthesia and allodynia over affected dermatome; motor exam of upper and lower limbs normal
• Other systems: Cardiovascular and respiratory exam unremarkable

Investigations

• Random capillary blood glucose: 12.2 mmol/L (220 mg/dL) (elevated)
• HbA1c (recent within 3 months): 8.1% (65 mmol/mol)
• CBC: WBC 9.5 x10^9/L (normal to mildly elevated)
• CRP: 15 mg/L (mildly elevated)
• Creatinine: 120 µmol/L (eGFR ~45 mL/min/1.73 m^2) (CKD stage 3)
• Lesion swab PCR for VZV: positive (if performed)

Diagnosis

Primary diagnosis: Herpes zoster (shingles)

• Evidence: Elderly patient with classic prodromal unilateral burning pain for several days followed by grouped vesicular rash in a single dermatomal distribution that does not cross the midline; PCR from lesion positive for VZV.

Differential diagnoses:

• Contact dermatitis/allergic reaction — often more diffuse and pruritic rather than painful; unlikely given prodromal neuropathic pain and dermatomal pattern.
• Herpes simplex infection — tends to cause smaller clustered vesicles recurrently in mucocutaneous sites; distribution and prodrome favour VZV.
• Cellulitis — would present as more confluent erythema, warmth and spreading, less vesicular and not dermatomal.
• Insect bite reaction — usually localized without preceding dermatomal neuropathic pain and less likely to form dermatomal vesicular band.

Management

• Antiviral therapy: Start oral valacyclovir (e.g., 1 g three times daily) as soon as possible; adjust dose for renal impairment (with eGFR ~45 consider standard dose but check local renal dosing — if eGFR lower, reduce dose or consider acyclovir IV if severe).
• Pain control: Regular paracetamol and consider short course weak opioid if required; start gabapentin low dose and titrate for neuropathic pain (monitor renal function and adjust dose); avoid NSAIDs if poorly controlled blood pressure/CKD concerns.
• Skin care: Keep lesions clean and dry; advise against scratching; topical calamine or antiseptic dressings for comfort.
• Infection control/avoidance: Advise to avoid contact with pregnant women who haven’t had chickenpox and severely immunocompromised people until lesions crusted.
• Monitoring and referral: Arrange follow-up to review pain and rash; urgent referral to ophthalmology if any facial or periocular involvement develops; consider hospital admission/IV acyclovir if disseminated disease, severe pain, or significant immunosuppression.
• Address comorbidity: Review glycaemic control and optimize diabetes management; consider shingles (zoster) vaccination once recovered and according to local guidance.

Key Learning Points

• Herpes zoster typically presents with a prodrome of unilateral neuropathic pain followed by a grouped vesicular rash in a single dermatome that does not cross the midline.
• Early antiviral therapy (ideally within 72 hours of rash onset) reduces viral replication and may reduce complications; dose adjustment is necessary in renal impairment.
• In older patients and those with comorbidities (eg, diabetes, CKD), monitor for complications including postherpetic neuralgia and secondary bacterial infection; manage pain proactively and consider vaccination after recovery.