Both lichen planus and psoriasis can cause patches of scaly bumps or rashes on the skin. A doctor can usually tell the conditions apart with a physical exam, though they may need further tests to diagnose the condition.
This article explores the similarities and differences between lichen planus and psoriasis, including their symptoms, causes, and treatments.
What are lichen planus and psoriasis?
Lichen planus and psoriasis both cause bumps or rashes on the skin.
Lichen planus and psoriasis are two unrelated skin conditions. They have some similar symptoms but different causes and treatments. Getting a correct diagnosis is an important step toward the right treatment.
Lichen planus is a common inflammatory skin condition. It is not contagious and not a sign of cancer. It appears as firm, shiny, reddish bumps.
Psoriasis is the most common autoimmune condition in the United States. It is also not contagious or a sign of cancer.
People with psoriasis develop thick, red patches of irritated skin, which are often covered with silver or white scales. These patches are called plaques.
There are five main types of psoriasis:
Plaque psoriasis and guttate psoriasis are the types most likely to be confused with lichen planus.
Image credit: Dermnet New Zealand.
Image credit: James Heilman MD, 2010.
What are the symptoms?
The table below explores the differences between the symptoms of lichen planus and psoriasis.
|Lichen planus symptoms||Plaque psoriasis symptoms|
|bumps that are raised, flat-topped, firm, shiny, and reddish or purple||thick, red patches of dry skin (plaques)|
|bumps that may have a white line through them||plaques that have white or silver scales|
|bumps that are sometimes itchy (in mild to severe cases)||plaques that are usually itchy (often severely) and may sting|
|a few bumps or many||plaques can vary in size|
|often affects the wrists, lower back, or ankles||often appears on the elbows, knees, scalp, or lower back|
|may appear under the fingernails, distorting their shape and sometimes causing nail loss, in the mouth as white dots or lines, or on the scalp, possibly causing hair loss||can cause thickened, yellow fingernails or toenails|
|unclear what triggers flare-ups||weather, stress, skin injury, and smoking can trigger flares|
|symptoms usually go away without treatment after about a year||symptoms are long-term, with no known cure|
Who do they affect?
Psoriasis is more common than lichen planus.
- Psoriasis affects 2.2 percent of people in the U.S.
- Lichen planus affects around 1 percent of the population.
The conditions are equally common in males and females, but lichen planus more frequently affects the mouth in females.
Both conditions can occur at any age. However:
- Lichen planus is most common in middle-aged adults.
- Psoriasis most often appears in people ages 15–25.
How long do they last?
A key difference between lichen planus and psoriasis involves the duration of symptoms.
Lichen planus usually goes away without treatment after about a year, but it can last longer.
In contrast, psoriasis is often a long-term condition, and there is no cure. People can usually manage the symptoms with ointments, medication, lifestyle changes, or a combination.
Which body parts do they affect?
Lichen planus lesions often affect the:
- mouth (inside)
- lips (on or around)
- lower back
- fingernails or toenails (underneath)
Psoriasis plaques can develop anywhere on the body, but they most often appear on the:
- lower back
Some medications may cause a psoriasis flare-up.
Psoriasis is an autoimmune condition. This means that it results from a problem with the immune system that causes the body to mistakenly attack healthy cells. In response, skin cells multiply too rapidly, leading to buildups of cells that become plaques.
Doctors do not yet understand what causes lichen planus. It may also be an autoimmune condition, but scientists have not yet confirmed a link.
Psoriasis flare-ups may be triggered by:
- not enough sunlight
- dry air
- dry skin
- insect bites
- bacterial or viral infections
- certain medications
Doctors have likewise reported lichen planus developing in response to certain medications. It can also occur as a complication of chronic hepatitis C.
If a person suspects that they have lichen planus or psoriasis, they should see a doctor for a diagnosis.
Doctors diagnose skin conditions by examining a person's skin. They will ask about symptoms, recent life changes, and family history.
The doctor may also perform a biopsy, which involves taking a small sample of skin to examine under a microscope. This helps them diagnose or rule out certain conditions.
Stress management techniques may help reduce psoriasis flare-ups.
Lichen planus does not usually require treatment. It often goes away by itself within a year.
If a person has particularly itchy or painful outbreaks, a doctor may prescribe topical corticosteroids or light therapy.
Psoriasis is a long-term condition, but people can usually manage their symptoms well.
Treatment options for psoriasis include:
- topical treatments
- oral treatments
- light therapy
- systemic treatments, which are drugs that work throughout the body
- biologic drug therapy
Individuals can also manage psoriasis flare-ups by avoiding triggers. The following lifestyle adjustments may help:
- dietary changes
- not spending long periods in the sun
- managing stress, possibly by trying yoga or mindfulness techniques
Research suggests that women with lichen planus may have a higher risk of developing certain types of cancer, including that of the lip, tongue, or vulva.
People with psoriasis have an increased risk of the following conditions:
There is no guaranteed cure for lichen planus or psoriasis, but with a doctor's help, a person can usually manage the symptoms.
There are a number of treatment options for lichen planus and psoriasis. For example, topical medications and light therapy are common treatments for both.
Lichen planus usually goes away by itself. Most people only have it for a year, though it may reoccur. Psoriasis is a long-term condition that can be managed well with the right treatment plan.