Psoriasis

What is psoriasis?

Psoriasis is a chronic autoimmune condition that speeds up the life cycle of skin cells. New cells build up on the surface of the skin, forming thick, scaly patches called plaques. These plaques often appear on the scalp, knees, elbows, and lower back but can occur anywhere.

Types of psoriasis

  • Plaque psoriasis

    The most common type, causing raised, red patches covered with silvery scales.

  • Inverse psoriasis

    Occurs in skin folds, producing smooth, red patches without scales.

  • Guttate psoriasis

    Often triggered by infection, appears as small, drop-shaped lesions on the torso and limbs.

  • Nail psoriasis

    Affects fingernails and toenails, causing pitting, discoloration, and sometimes nail loss.

  • Pustular psoriasis

    Characterized by white pustules surrounded by red skin, can be localized or widespread.

  • Scalp psoriasis

    Affects the scalp, ranging from fine scaling to thick, crusted plaques.

  • Erythrodermic psoriasis

    A rare, severe form covering most of the body in red, peeling skin and requiring urgent care.

Causes and risk factors

  • Immune system dysfunction involving T cells and neutrophils
  • Family history of psoriasis
  • Stress and emotional triggers
  • Skin injury such as cuts, scrapes, or sunburn
  • Infections, especially streptococcal throat infections
  • Certain medications (lithium, beta-blockers, antimalarials)
  • Cold, dry weather
  • Obesity and metabolic factors

Symptoms

  • Red patches of skin covered with thick, silvery scales
  • Dry, cracked skin that may bleed
  • Itching, burning, or soreness around plaques
  • Thickened, pitted, or ridged nails
  • Joint pain, swelling, and stiffness (psoriatic arthritis)
  • Periods of flare-ups followed by remission

Diagnosis

  • Physical examination

    Dermatologist inspects skin, nails, and scalp for characteristic plaques and scales.

  • Medical history

    Review of family history, recent infections, medications, and symptom patterns.

  • Skin biopsy

    A small sample is examined under a microscope when diagnosis is uncertain.

  • Joint imaging

    X-rays or MRI may be used if psoriatic arthritis is suspected.

Treatment

Topical therapies

  • Corticosteroid creams and ointments
  • Vitamin D analogs
  • Retinoids
  • Calcineurin inhibitors
  • Salicylic acid and coal tar preparations

Phototherapy

  • Ultraviolet B (UVB) light
  • Psoralen plus UVA (PUVA)

Systemic medications

  • Oral retinoids
  • Cyclophosphamide and methotrexate
  • Cyclosporine
  • Biologic agents targeting TNF, IL-17, or IL-23

Lifestyle and home remedies

  • Regular moisturizing
  • Stress reduction techniques
  • Avoidance of known triggers
  • Balanced diet and healthy weight

Sources

  • American Academy of Dermatology. Psoriasis clinical guideline. Accessed Apr. 25, 2024.
  • Centers for Disease Control and Prevention. Psoriasis. Accessed Apr. 25, 2024.
  • National Library of Medicine. Psoriasis. Accessed Apr. 25, 2024.
  • National Psoriasis Foundation. About Psoriasis. Accessed Apr. 25, 2024.