10 psoriasis facts

• Psoriasis is a chronic inflammatory skin condition characterised by well-demarcated, scaly, erythematous plaques
• Prevalence in the UK is approximately 2%
• Genetic predisposition, environmental factors, and immune system dysfunction contribute to its development
• Diagnosis is primarily clinical, supported by history and physical examination
• Treatment options include topical treatments, light therapy, and systemic medications.

1. Definition

• Psoriasis is a chronic, non-communicable skin condition characterized by abnormal keratinocyte proliferation and immune system dysregulation.
• Results in inflammation and scaling of the skin, leading to significant physical and psychological morbidity.

Types

• Plaque psoriasis – is the most common type of psoriasis. About 80-90% have plaque psoriasis
• Inverse psoriasis– appears in skin folds. It causes thin plaques without scales
• Guttate psoriasis – may appear after a sore throat caused by a streptococcal infection. It looks like small, red, drop-shaped scaly spots and often affects children and young adults
• Pustular psoriasis – has small, pus-filled bumps on top of plaques
• Erythrodermic psoriasis – is a severe type of psoriasis that affects a large area (more than 90%) of your skin. which causes red and scaly skin over much of your body.
• Nail psoriasis – causes skin discoloration, pitting and changes to fingernails and toenails.

2. Epidemiology

• Estimated prevalence in the UK: 2% (approximately 1.5 million people)
• More common in Caucasians than other ethnic groups
• Peak onset: 20-30 years and 50-60 years
• Female-to-male ratio: 1:1.

• Family history (first-degree relative)
• Obesity
• Smoking
• Excessive alcohol consumption
• Stress
• Certain medications (e.g. lithium, beta-blockers)
• Infections (e.g. streptococcal infections).

• Genetic predisposition (HLA-Cw6, PSORS1)
• Immune system dysfunction (T-cell activation, cytokine imbalance)
• Environmental triggers (e.g. skin trauma, cold weather)
• Abnormal keratinocyte proliferation and differentiation.

• Well-demarcated, erythematous plaques with silvery scales

• Commonly affected areas: elbows, knees, scalp, lower back
• Itching, burning, or stinging sensations
• Skin cracking and bleeding
• Nail changes (e.g. pitting, onycholysis)

• Joint pain or stiffness (psoriatic arthritis).

• Primarily clinical, based on history and physical examination
• Characteristic skin lesions and distribution
• Supportive features: nail changes, scalp involvement.

• Skin biopsy (to confirm diagnosis or rule out other conditions)
• Blood tests (e.g. inflammatory markers, liver function)
• Joint imaging (e.g. x-rays, ultrasound) for suspected psoriatic arthritis.

• Eczema (atopic dermatitis)
• Seborrhoeic dermatitis
• Contact dermatitis
• Lichen planus
• Cutaneous lupus erythematosus.

7. Treatment

• Topical treatment
  • Corticosteroids
  • Vitamin D analogues (e.g. calcipotriol)
  • Topical retinoids
• Light therapy
  • UVB phototherapy
  • Psoralen plus UVA (PUVA)
• Systemic medication
  • Methotrexate
  • Cyclosporin
  • Biological agents (e.g. etanercept, adalimumab)
• Lifestyle modification
  • Weight management
  • Smoking cessation
  • Stress reduction.

• New onset of skin lesions or symptoms
• Worsening or unresponsive symptoms
• Joint pain or stiffness
• Suspicion of complications (e.g. skin infections, eye problems).

• Skin infections (e.g. bacterial, fungal)
• Eye problems (e.g. uveitis, conjunctivitis)
• Psoriatic arthritis
• Cardiovascular disease
• Depression and anxiety.

• Chronic condition with variable disease course
• Response to treatment varies between individuals
• Early treatment and lifestyle modifications can improve outcomes.

• Maintain a healthy lifestyle (e.g. balanced diet, regular exercise)
• Manage stress
• Avoid triggers (e.g. smoking, excessive alcohol, drugs known to cause or worsen psoriasis)
• Regular skin checks and monitoring for complications.

Summary

We have described 10 facts about psoriasis. We hope it has been helpful.

Top Tip

If psoriasis is not improving, arrange a dermatology opinion (partly to consider biological agents).

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