Types of Psoriasis

Knowing what type of psoriasis you have can help you and your doctor come up with an effective treatment plan.

Your physician can usually diagnose the form based on your symptoms and a careful skin examination. But a biopsy is sometimes needed for confirmation.

Because psoriasis can look like other skin conditions that cause itchy, scaly rashes with inflammation, it is often confused with various disorders. These may include common skin conditions, such as eczema, heat rash, types of skin cancers, and dandruff. Psoriasis can also resemble and be confused with the fungal infection known as ringworm.

Most people have just one kind of psoriasis, but you can develop a new type of the skin disorder at any time. (1)

Plaque psoriasis, also called psoriasis vulgaris, is the most common type.

Between 80 and 90 percent of people with psoriasis have this form. (2)

Plaque psoriasis is characterized by raised, scaly patches of skin. On white skin, the patches, known as plaques, are often red or pink, with silvery-white scale. On skin of color plaques may appear salmon with silvery-white scale, or violet or dark brown with gray scale.

Plaques can crop up on any area of the body but are commonly found on the knees, elbows, scalp, or back.

The plaques can cause:

• Burning
• Pain
• Itchiness
• Cracking
• Bleeding

Guttate psoriasis is the second most common psoriasis type, affecting about 8 percent of people with psoriasis. (3)

Guttate psoriasis, from the Latin for “raindrop shaped,” causes small, dot-like spots on the body. These lesions frequently appear on the upper arms, trunk, thighs, or scalp.

Often, this form of psoriasis starts in childhood or young adulthood.

Guttate psoriasis can be triggered by a strep infection, tonsillitis, stress, a skin injury, or certain medication (such as beta-blockers). Sometimes genetic factors are to blame.

Guttate psoriasis may clear up on its own, but certain cases require treatment. Some patients may experience guttate psoriasis just once, while others may find it leads to plaque psoriasis.

This uncommon form of psoriasis most often affects adults.

Pustular psoriasis is characterized by pus-filled bumps (called pustules) surrounded by inflamed and reddened or otherwise discolored skin. These blisters contain white blood cells and are not infectious or contagious. (4)

The bumps may cause:

• Soreness
• Pain

The pustules can appear on any part of the body but most often show up on the hands or feet.

When the bumps dry out, they can leave behind brown dots or scales on the skin.

Some triggers may increase your risk of developing this form of psoriasis. These include:

• Systemic steroid medication
• Suddenly stopping the use of certain medication, including topical steroid medicines
• Pregnancy
• Infection
• Stress
• Too much sunlight
• Certain chemicals

Occasionally, the pustules can cover the entire body, which is known as generalized pustular psoriasis, or von Zumbusch psoriasis. This is a serious condition that requires immediate medical attention.

Symptoms of generalized pustular psoriasis include:

• Fever
• Nausea
• Chills
• Bright red skin
• Fatigue
• Muscle weakness
• Severe itching
• Loss of appetite
• Fast heart rate

With inverse psoriasis, people develop smooth, shiny lesions in body folds. On skin of color the lesions may be purplish, brown, or darker than the surrounding skin, while on white skin the lesions are bright red.

These lesions typically appear on creased areas of the body where skin meets skin, such as the underarms, behind the knees, under the breasts, near the buttocks and genitals, or on the groin.

This condition can cause sore skin, which may worsen if you sweat or rub the area.

It’s sometimes triggered by a buildup of yeast.

Some people who develop inverse psoriasis also suffer from another form of psoriasis. (5)

This is an uncommon but very serious form of psoriasis. About 2 percent of people with psoriasis will develop erythrodermic psoriasis in their lifetime. (6)

This type usually occurs in people who have uncontrolled plaque psoriasis.

Erythrodermic psoriasis causes extremely red or otherwise discolored skin that affects most of the body. (6)

Symptoms include:

• Burning
• Peeling
• Severe itching
• Pain
• Fast heart rate
• Change in body temperature

If you have erythrodermic psoriasis, you’ll need immediate treatment, as it can be a life-threatening condition.

This form of psoriasis can cause complications, such as protein and fluid loss, infection, pneumonia, severe swelling, or congestive heart failure.

Erythrodermic psoriasis may be triggered by:

• A severe sunburn
• An allergic reaction to a medicine
• Suddenly stopping psoriasis treatment
• An infection
• Certain drugs, such as lithium, cortisone, antimalarial medicines, or coal tar products

When psoriasis affects the fingernails or toenails, it’s known as nail psoriasis. (7)

This type can cause symptoms such as:

• Discoloration of nails
• Red or white spots underneath the nails
• Abnormal nail growth
• Pitting (small pinprick holes) on nails
• Ridges or grooves in your nails
• Lifting of the nail away from the skin
• Crumbling of nails

Many people with plaque psoriasis also have nail psoriasis. For some, however, a single nail involvement may be the only form of psoriasis they develop.

Scalp psoriasis shows up as itchy, scaly patches on the scalp that may bleed if you try to remove them. (8)

About half of people who have psoriasis have it on their scalp.

At the onset, scalp psoriasis often is confused with seborrheic dermatitis (aka dandruff). Dandruff is a flaky, itchy scalp without signs of inflammation (such as discoloration or swelling).

Scalp psoriasis can spread beyond the hairline and affect the forehead, back of the neck, and areas around the ears.

Often psoriasis in kids is first found on the scalp.

Additional reporting by George Vernadakis