National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Pityriasis lichenoides chronica

Información en español


Categories:
This disease is grouped under:
Pityriasis lichenoides chronica (PLC) is a skin disease that causes the development of small, scaling, raised spots (papules) on the skin. PLC is the relatively mild form of the disease pityriasis lichenoides. A person with PLC tends to have multiple episodes of papules on the skin lasting for months or a few years, meaning the disease is chronic. The papules develop gradually. They first appear pink and scaly, and they gradually flatten and become brown in color over a period of weeks or months. Papules at various stages may be present at any one time.[1]

The cause of PLC is unknown, but it is not contagious. There are several theories about the cause of the disease, including that it may be a response by the immune system to an infection or medication.[1][2] Diagnosis of PLC is based on a doctor observing papules on the skin. A skin biopsy may be used to confirm the diagnosis. Treatment options may include antibiotics, creams for the skin, or phototherapy. In severe cases, medications that suppress the immune system response (immunosuppressants) may be used.[1][2]
Last updated: 4/28/2018
The signs and symptoms of pityriasis lichenoides chronica (PLC) include the development of papules on the skin. The papules typically begin as small, firm, pink spots, and they may have a scaly layer on the top. Over time, the papules typically turn brown in color and eventually fade. This process may occur over a few weeks.[1][2][3]

The most common locations for the papules are the trunk, buttocks, arms, and legs. Rarely, the papules may also occur on the hands, feet, face, and scalp. The papules typically are located in groups, and are generally not painful or itchy.[1][3] The papules can resemble those associated with psoriasis, chicken pox, or insect bites.[3]

PLC is a chronic disease, meaning that some people experience the development of new papules after old papules have faded. This can last for several months to several years.[2] PLC most commonly affects adolescents and young adults. The disease may be slightly more common in males.[1][2]
Last updated: 4/28/2018
The exact cause of pityriasis lichenoides chronica (PLC) is not well-understood. In some cases, people with PLC have also had infections including Ebstein-Barr virus (EBV), toxoplasmosis, cytomegalovirus, and human immunodeficiency virus (HIV). It is thought that these infections may increase the risk of developing PLC.[1] In some cases, people have developed PLC after taking medications such as chemotherapy or hormone replacement therapy. These medications may also increase the risk of developing PLC.[4]

There is some evidence that PLC could be caused by the overgrowth of cells of the lymphatic system (lymphoproliferative disorder). PLC could also be caused by a reaction of the immune system against the body’s own tissues (autoimmune response).[1][2] However, the cause of PLC may be different for different people with the disease, and the exact cause of the disease may not be determined for each person. PLC is not contagious, so it cannot be spread by coming in contact with a person who has the skin papules.[1][2]
Last updated: 4/28/2018
Pityriasis lichenoides chronica (PLC) is not thought to be passed directly from parents to children. This is because there is not one specific gene in which changes are thought to cause PLC. The development of PLC may be associated with having certain kinds of infections, or it may be caused by the immune system attacking the tissues of the body (autoimmune response).[1] In general, autoimmune responses are thought to be caused by a combination of genetic and environmental factors. If the cause of PLC can be determined for a specific person and family members have similar risk factors, they may have an increased risk to develop PLC as well.
Last updated: 4/28/2018
Pityriasis lichenoides chronica (PLC) may be suspected when a doctor, most often a dermatologist, observes papules on the skin that look like those associated with PLC. These papules can also look like those that are caused by other diseases including psoriasis, chicken pox, or insect bites. Therefore, a skin biopsy may be recommended to confirm the diagnosis.[2][3]
Last updated: 4/28/2018
In some cases, pityriasis lichenoides chronica (PLC) may fade over time without requiring any treatment. In other cases, people with PLC may want treatment because there are many papules that are taking a long time to fade. Possible therapies that may be used to treat PLC include:[1][2]
If these therapies do not help treat PLC, other treatments may be used including oral steroids and immunosuppressants.[1][2] In some cases, PLC may not respond to treatment, and relapses may occur. If the papules do return, close follow-up with a dermatologist is recommended.[2]

More information about specific medications that may be used to treat PLC is available on Medscape Reference’s website.
Last updated: 4/28/2018
Most people with pityriasis lichenoides chronica (PLC) notice that their symptoms improve over time. The exact amount of time that people have symptoms of the disease can vary, but typically the papules are present for several months to a few years. In some cases, the papules may disappear and reappear (relapse) over time.[2]

For some people, treatment helps to shorten the duration of the disease. Some treatments, such as steroids or antibiotics, may cause side-effects.[5] Some people may need to try a combination of treatments to find what works best in relieving the symptoms.[2] In some cases, treatment may not relieve the symptoms of PLC.[6] Rarely, people with PLC may develop a specific type of lymphoma of the skin (cutaneous lymphoma).[7]
Last updated: 4/28/2018

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • The British Association of Dermatologists provides an informational leaflet on pityriasis lichenoides.  Click on the British Association of Dermatologists link to view this leaflet.
  • DermNet NZ is an online resource about skin diseases developed by the New Zealand Dermatological Society Incorporated. DermNet NZ provides information about this condition.

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Pityriasis lichenoides chronica. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.

  1. Ngan, V. Pityriasis lichenoides. DermNet NZ. https://www.dermnetnz.org/topics/pityriasis-lichenoides/. Accessed 4/21/2018.
  2. Haeberie MT and Callen JP. Pityriasis Lichenoides. Medscape. April 17, 2017; http://emedicine.medscape.com/article/1099078-overview.
  3. Pityriasis Lichenoides. British Association of Dermatologists. September 2016; http://www.bad.org.uk/shared/get-file.ashx?id=115&itemtype=document.
  4. Khachemoune A and Blyumin ML. Pityriasis lichenoides: pathophysiology, classification, and treatment. Am J Clin Dermatol. 2007; 8(1):29-36. https://www.ncbi.nlm.nih.gov/pubmed/17298104.
  5. Maranda EL, Smith M, Nguyen AH, Patel VN, Schachner LA, and Joaquin JJ. Phototherapy for Pityriasis Lichenoides in the Pediatric Population: A Review of the Published Literature. Am J Clin Dermatol. December 2016; 17(6):583-591. https://www.ncbi.nlm.nih.gov/pubmed/27502793.
  6. Zang JB, Coates SJ, Vonderheid EC, and Cohen BA. Pityriasis lichenoides: Long-term follow-up study. Pediatric Dermatology. March 2018; 35(2):213-219. https://www.ncbi.nlm.nih.gov/pubmed/29315771.
  7. Zaaroura H, Sahar D, Bick T, and Bergman R. Relationship Between Pityriasis Lichenoides and Mycosis Fungoides: A Clinicopathological, Immunohistochemical, and Molecular Study. American Journal of Dermatopathology. November 22, 2017; https://www.ncbi.nlm.nih.gov/pubmed/29210716.