Family Medicine · Year 3 · from Family Medicine

Case 1: Psoriasis

Patient Demographics

  • Age: 35 years old
  • Sex: Male
  • Occupation: Sales representative

Chief Complaint

"I have these red, scaly patches on my elbows and knees that won't go away. They're embarrassing."

History of Present Illness

Mr. Christopher Adams is a 35-year-old man presenting with a 6-month history of red, scaly patches on his elbows, knees, and lower back. The patches are mildly itchy but mostly a cosmetic concern. He first noticed small patches on his elbows that gradually enlarged and spread. He has tried over-the-counter hydrocortisone with minimal improvement. He reports the skin flakes onto his dark clothing, which he finds embarrassing at work. He recently noticed similar changes on his scalp with flaking. No joint pain or swelling.

He reports increased stress at work recently, and symptoms seem to worsen during stressful periods.

Past Medical History

  • No chronic medical conditions
  • No prior skin conditions

Family History

  • Father: Psoriasis
  • Mother: Type 2 diabetes
  • No family history of autoimmune diseases

Social History

  • Social drinker (3-4 beers on weekends)
  • Non-smoker
  • Single, lives alone
  • High-stress job with frequent travel

Physical Examination

  • Vital Signs: BP 124/78 mmHg, HR 72, BMI 27
  • General: Well-appearing male, mildly overweight
  • Skin:
  • Bilateral elbows: Well-demarcated, erythematous plaques with thick, silvery-white scale, 3-5 cm
  • Bilateral knees: Similar plaques, 2-4 cm
  • Lower back: One plaque, 4 cm
  • Scalp: Erythematous patches along hairline with white scale
  • Auspitz sign positive (pinpoint bleeding with scale removal)
  • Nails: Pitting on several fingernails, no onycholysis
  • No involvement of face, palms, soles, or groin
  • Musculoskeletal: No joint swelling, tenderness, or deformity
  • Body Surface Area (BSA) involved: Approximately 4%

Clinical Image

Image: Psoriatic plaques demonstrating characteristic features including well-demarcated erythematous plaques with silvery-white scale, commonly seen on extensor surfaces and lower back.

Image Source: Wikimedia Commons Attribution: Eisfelder, CC BY-SA 3.0 URL: https://commons.wikimedia.org/wiki/File:Psoriasis_on_back1.jpg

Assessment and Diagnosis

  1. Plaque psoriasis, mild-moderate - Classic presentation with well-demarcated erythematous plaques with silvery scale on extensor surfaces
  2. Scalp psoriasis - Common extension
  3. Nail psoriasis - Pitting indicative of psoriatic nail involvement
  4. No current psoriatic arthritis - Important to screen given nail involvement (risk factor)

Management Plan

Topical Therapy (First-line for Limited Disease):

  • High-potency topical corticosteroid: Betamethasone dipropionate 0.05% ointment BID to body plaques
  • Limit to 2-4 weeks continuous, then use intermittently
  • Medium-potency for scalp: Fluocinonide solution for scalp daily
  • Calcipotriene (vitamin D analog) 0.005% cream: Apply daily as steroid-sparing agent
  • Combination product: Calcipotriene/betamethasone dipropionate foam - once daily, effective and well-tolerated

For Scalp:

  • Tar-based shampoo (OTC) 2-3 times weekly
  • Leave-on scalp treatments: Fluocinonide solution or clobetasol foam
  • Calcipotriene scalp solution

For Nail Psoriasis:

  • Difficult to treat topically
  • Monitor for progression
  • May improve with systemic therapy if needed in future

Lifestyle Modifications:

  • Stress management (psoriasis flares with stress)
  • Weight loss (obesity associated with more severe psoriasis)
  • Limit alcohol (can worsen psoriasis and interfere with some treatments)
  • Smoking cessation counseling (he doesn't smoke, but confirm)
  • Moisturize frequently (reduces scale, improves barrier)

Screening Considerations:

  • Monitor for psoriatic arthritis at each visit (PASE questionnaire)
  • Screen for metabolic syndrome (obesity, hypertension, diabetes, dyslipidemia) - higher risk in psoriasis
  • Consider depression screening (high comorbidity)

Follow-Up

  • Return in 6-8 weeks to assess topical response
  • If inadequate response (BSA >10%, affecting quality of life), consider:
  • Phototherapy (UVB) - referral to dermatology
  • Systemic therapy (methotrexate, apremilast, biologics) - dermatology referral
  • Annual skin cancer screening (if on phototherapy)

Teaching Points

  1. Psoriasis recognition: Well-demarcated erythematous plaques with silvery-white scale on extensor surfaces (elbows, knees), scalp, and lower back. Auspitz sign (pinpoint bleeding with scale removal) is characteristic.
  1. Psoriatic arthritis screening: 30% of psoriasis patients develop psoriatic arthritis. Nail involvement increases risk. Ask about joint pain, stiffness, swelling, and sausage digits (dactylitis).
  1. Treatment approach by severity:
  • Mild (<5% BSA): Topical therapy (corticosteroids, vitamin D analogs)
  • Moderate (5-10% BSA): Topical + phototherapy or consider systemic
  • Severe (>10% BSA or significant QOL impact): Systemic therapy, biologics
  1. Comorbidities: Psoriasis is associated with metabolic syndrome, cardiovascular disease, depression, and inflammatory bowel disease. Screen appropriately.

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