What happens in the skin with psoriasis?

Inflammation involving the immune system changes the skin-cell cycle. Skin cells build up at the surface and can form thickened or scaly areas, but their shape, colour, and thickness can vary by psoriasis type, body area, and skin tone.

Do not rely only on the phrase ‘silvery scale.’ Inflammation may look pink, red, purple, dark brown, or grey on different skin tones, and temporary darker or lighter marks may remain after a flare settles. Clinicians therefore assess the rash, its location, scalp, nails, joints, and history together.

[1, 2, 3]

Where should you start if you think you may have psoriasis?

Notice where the rash occurs, how long it has been present, whether it itches or hurts, and whether you have nail changes or joint pain and swelling. Bring that information to a clinician. Diagnosis is usually based on the skin, scalp, and nail examination plus your history, with additional tests when the pattern is unclear.

After diagnosis, a care plan considers the type and site of psoriasis, severity, effects on sleep, work, relationships and mental wellbeing, other conditions, current medicines, and the suitability of each option. Do not use another person's treatment plan as a substitute for your own assessment.

  • Learn about psoriasis types and locations so you know what to mention.
  • Understand how psoriasis is assessed and which conditions can look similar.
  • Review the broad options from topical treatment and phototherapy to systemic medicines.
  • Record skin, nail, and joint symptoms, possible patterns, and effects on daily life before a visit.

[4, 3]

Which symptoms should not be watched at home?

Seek urgent same-day assessment if widespread skin redness or colour change and tenderness develops quickly, or if widespread pustules occur with fever, chills, a fast heartbeat, or feeling very unwell. Generalised pustular and erythrodermic psoriasis can be serious.

Tell a clinician about recurring joint pain, swelling, or stiffness, especially in the morning, a whole swollen finger or toe, or heel pain. These symptoms should be assessed for psoriatic arthritis even when the skin disease is not severe.

[3, 5, 6]

References

These references informed the source copy and are not personal medical advice.

  1. Psoriasis — Institute of Dermatology, Department of Medical Services. Institute of Dermatology, Thailand Department of Medical Services. 2025.
  2. Psoriasis: Overview. American Academy of Dermatology. current patient guidance.
  3. Psoriasis: assessment and management (CG153) — Recommendations. National Institute for Health and Care Excellence. 2012; revised 2017; minor updates 2025.
  4. Psoriasis: Diagnosis and treatment. American Academy of Dermatology. current patient guidance.
  5. Types of psoriasis and serious warning signs. American Academy of Dermatology. current patient guidance.
  6. Psoriatic arthritis: Symptoms. American Academy of Dermatology. current patient guidance.