Pityriasis rosea – everything you need to know

Pityriasis rosea is a common, harmless skin disease that causes a pinkish maculopapular rash on the body’s skin. This disease is common among individuals aged 15 to 30, and its treatment is limited. The worldwide prevalence rate is between 0.5% to 2%. This skin disease is interesting because there are many variations in observed symptoms, and its etiology is not yet fully understood. It can easily be mistaken for other conditions such as Tinea corporis, Tinea versicolor, secondary syphilis, guttate psoriasis, or dermatitis.

Characteristic symptoms

The disease begins with the appearance of a pink, scaly spot (also known as the Herald patch) on the trunk, and less commonly on the limbs. The primary spot appears in 50% to 90% of patients. After the appearance of the primary spot, smaller pink maculopapular spots spread across the body over a period of seven to fourteen days. It rarely appears on the face and neck, but such cases have been documented. The rash may sometimes resemble the shape of a Christmas tree. The spots are scaly, and itching is reported in affected individuals, although it is not a necessary symptom. The rash stops spreading on the body after a maximum of one month, but resolution can take up to five months.

It is very rare for this disease to last for months or even years, and the cause remains unknown.

Potential causes

In the search for the causative agent, pityriasis has been linked to viruses and bacteria such as cytomegalovirus, Epstein–Barr virus, parvovirus B19, influenza virus, Legionella spp., Mycoplasma spp. However, it has been proven that pityriasis is not directly associated with them.

Pityriasis most commonly appears after the affected person has had some respiratory infection. Today, it is mainly believed that the cause of pityriasis are herpes viruses, especially Herpes simplex virus 6 and Herpes simplex virus 7. These viruses are not direct causes of the disease. Pityriasis rosea is actually a result of a reactive response to the systemic replication of the viruses.

Treatment options

The treatment of pityriasis is quite limited due to a lack of scientifically proven facts about the disease. Steroids are prescribed to most patients (especially if there is severe itching), along with antivirals, macrolides, and it is recommended to care for the skin with gentle lotions and emulsions. In most cases, it resolves on its own and does not require treatment.

Phototherapy is one possible way to expedite the treatment of this disease. The affected person is exposed to quartz lamps that emit UV-A and UV-B rays. Further research on this approach is still needed due to diverse patient reactions to phototherapy.