Medically reviewed by Dr. A.M. van Coevorden, dermatologist
Lichen planusItchy bumps with a pattern of their own.
Lichen planus is an intensely itchy inflammation of the skin with small, purplish-red, flat-topped bumps. The condition can also affect the lining of the mouth and genitals, the nails and the scalp. Lichen planus is not contagious. On the skin the symptoms often clear by themselves within two years; on the mucous membranes the condition is usually more persistent.
What is lichen planus?
Lichen planus starts as small, brick-red to purple, flat-topped bumps of a few millimetres, often grouped together and able to merge into larger patches. On the surface, very fine white lines can be seen on close inspection, known as Wickham's striae; these are characteristic of the condition. Preferred sites are the wrists, feet and lower legs, but patches can appear anywhere. In the mouth, lichen planus looks different: a white, lace-like network on the inside of the cheeks, sometimes with painful open patches. The nails and scalp can also be involved.
How does lichen planus develop?
The cause of lichen planus is unknown. It is an inflammatory reaction in which the body's own immune system plays a role; it is not an infection and you cannot pass it on to anyone else. Characteristically, a new lichen planus patch can appear where the skin has been damaged, for instance by a scratch. Doctors call this the Koebner phenomenon.
What can you do yourself?
Treat your skin gently and try to prevent damage: no scratching, no scrubbing, no harsh products. New patches tend to appear precisely where skin is damaged. If you have lichen planus on the genitals, protect the fragile skin from pressure and friction: avoid tight clothing and adjust your bicycle saddle if needed. For patches in the mouth, it helps to avoid sharp, acidic and hot food and drink when they hurt.
Please note
Scratching and damaging the skin backfire: a new lichen planus patch can appear at the site of an injury.
When to see a dermatologist or doctor?
Have your skin assessed if you have itchy bumps that don't clear, especially if you can see the fine white lines on them; lichen planus can resemble other skin conditions and a dermatologist recognises the picture. Treatment is only needed if you have symptoms. For the skin, a corticosteroid ointment is usually the first step; it reduces the itch and the rash. For extensive lichen planus, the dermatologist may suggest light therapy or tablet treatment. For the mouth there are special ointments, gels and rinses. After healing, dark brown patches often remain; these usually fade slowly by themselves. Lichen planus can return after years; if it does, see your doctor again.
Please note
Do you have painful open patches in your mouth or on your genitals? Always have those assessed; mucosal lichen planus is often persistent and deserves targeted treatment.
Frequently asked questions
Is lichen planus contagious?
No. Lichen planus is an inflammatory reaction in which the body's own immune system plays a role, not an infection. You cannot pass it on to anyone else, not even through touch or intimate contact.
Does lichen planus clear by itself?
On the skin, there is a good chance the symptoms clear by themselves within two years. On the mucous membranes, such as in the mouth, lichen planus is usually more persistent. After healing, the condition can return after years; why is unknown.
Where do the dark patches after lichen planus come from?
After the bumps disappear, dark brown patches often remain, because the inflammation has left extra pigment in the skin. These patches usually fade slowly by themselves, though this can take months.
What is the difference between lichen planus and psoriasis?
Both cause patches on the skin, but they look different. Lichen planus causes purplish-red, flat-topped bumps with fine white lines, often on the wrists and lower legs, and usually itches intensely. Psoriasis causes thicker red patches with silvery-white scales, mainly on the elbows, knees and scalp. A dermatologist can tell the difference at a glance.
When should you see a dermatologist about lichen planus?
With itchy bumps that don't clear, with painful or open patches in the mouth or on the genitals, with nail abnormalities, and when the symptoms limit your daily life. The dermatologist makes the diagnosis and tailors the treatment to the location and severity.
Sources and more information
- Lichen planus (nvdv.nl)