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Symptoms and diagnosis - Psoriasis

Psoriasis is a skin condition that causes red patches of skin which are dry and flaky (scaly).

You can get it on areas such as your scalp, elbows or knees. But you can get it anywhere on your body. It depends on the type of psoriasis you have. Some types only affect certain parts of your body.

Symptoms of psoriasis

On white skin the patches can look pink or red, and the scales white or silvery.

On brown and black skin the patches can look pink, red, purple or dark brown. The scales may look grey, white or silvery.

You may find that psoriasis causes your skin to become itchy or sore.

Psoriasis can come and go and may be mild or moderate to severe.

Diagnosing psoriasis

Non-urgent advice: Talk to your GP if:

  • you think you may have psoriasis

They can check if you have it and help you get the treatment you need.

Urgent advice: Contact your GP or out-of-hours GP for an urgent appointment if you:

  • have intense itching or burning that comes on suddenly
  • get pus-filled blisters (pustules) on a wide area of skin in a short space of time

These may be symptoms of rare types of psoriasis that you need emergency treatment for.

You will need an urgent referral from your GP to a dermatologist and admission to hospital.

Common types of psoriasis

The most common types of psoriasis include plaque psoriasis, scalp psoriasis and nail psoriasis.

Plaque psoriasis (psoriasis vulgaris)

Plaque psoriasis (psoriasis vulgaris) is the most common type of psoriasis. More than 8 in 10 cases of psoriasis are plaque psoriasis.

You will have dry red skin lesions (called plaques), which are covered in scales.

They usually appear on your elbows, knees, scalp and lower back. But they can appear anywhere on your body. The plaques can be itchy or sore, or both. In severe cases, the skin around your joints may crack and bleed.

Scalp psoriasis

Scalp psoriasis is a type of plaque psoriasis.

You can get it on parts of your scalp or on the whole scalp.

Patches of your scalp are covered in thick scales (dry and flaky). It may cause your scalp to become itchy.

In extreme cases, it can cause hair loss, but this is usually only for a short time.

Scalp psoriasis -

Guttate psoriasis

Guttate psoriasis causes small drop-shaped spots. You will get these on your chest, arms, legs and scalp.

Sometimes you can get it after a streptococcal throat infection.

It is more common among children and teenagers.

There's a good chance guttate psoriasis will go away after a few weeks. But in some cases it can develop into plaque psoriasis.

Inverse (flexural) psoriasis

Inverse psoriasis affects parts of your body where there are folds or creases in your skin. This could be your armpit, groin, bottom or under your breasts. It can cause large, smooth patches in some or all these areas.

Friction and sweating can make inverse psoriasis worse. This means you can be uncomfortable in hot weather.

Nail psoriasis

Psoriasis can affect your nails. This happens to less than half of people who get the condition.

It can cause your nails to:

  • develop tiny dents or pits
  • change colour or shape
  • become loose and separate from the nail bed
  • crumble - this only happens in severe cases

Nail psoriasis -

Less common types

There are a number of rarer types of psoriasis.

Pustular psoriasis

Pustular psoriasis causes pus-filled blisters (pustules) on your skin.

You can get it on different parts of the body.

Pustular psoriasis -

Palmoplantar pustulosis

You will get pus-filled blisters (pustules) on the palms of your hands and the soles of your feet.

They turn into circular, scaly spots that then peel off. Pustules may come back every few days or weeks.


You will get pus-filled blisters (pustules) on your fingers and toes.

They burst and leave bright red areas that may ooze or become scaly. These may lead to your nails changing shape. They may also be painful.

Types of psoriasis you need emergency treatment for

You will usually need emergency treatment if you have symptoms of either of these 2 types of psoriasis.

Erythrodermic psoriasis

This is a rare type of psoriasis. Your skin becomes red all over. You can have intense itching or burning.

Erythrodermic psoriasis can come on suddenly. You will usually need emergency treatment if you have it.

It can lead to:

  • infection
  • dehydration
  • heart failure
  • hypothermia
  • malnutrition
Generalised pustular psoriasis or von Zumbusch psoriasis

This is a rare and serious form of psoriasis where you get pus-filled blisters (pustules) on a large area of skin in a short space of time.

You will usually need emergency treatment if you have it.

The pustules may come back every few days or weeks. Von Zumbusch psoriasis can cause:

  • fever
  • chills
  • weight loss
  • tiredness

Psoriatic arthritis

Some people with psoriasis get psoriatic arthritis.

Psoriatic arthritis symptoms and diagnosis

You will have:

  • tenderness
  • pain and swelling in the joints and connective tissues
  • stiffness

It can affect any joint in the body, but often affects the hands, feet, knees, neck, spine and elbows. Most people develop psoriatic arthritis after psoriasis. But some people develop it before they have psoriasis.

Your GP will refer you to a specialist (rheumatologist) if they think you have it.

There's no test for psoriatic arthritis. A rheumatologist will look at your medical history. They will also do physical examinations, blood tests, X-rays and MRI scans.

Living with psoriatic arthritis -

Psoriatic arthritis -

Information about psoriasis -

Content supplied by the NHS and adapted for Ireland by the HSE

Page last reviewed: 8 June 2023
Next review due: 8 June 2026

This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 123.