Pityriasis Rosea

​​​What is pityriasis rosea?

It is a relatively common skin condition that causes a temporary rash of red scaly patches on the body. The first spot of the rash, known as ‘herald patch’, is often large and oval. Smaller spots usually begin to appear afterwards. They spread from the herald patch, resembling a pine-tree pattern. This rash often disappears on its own.

The cause of pityriasis rosea is still unknown; however, it is believed that it is the result of a viral infection. Dermatologists have found human herpes viruses in the rashes, blood, and saliva of people with pityriasis rosea. Several types of human herpes virus were found; however, these types, (HHV) 6 and HHV-7, cannot cause sores or genital herpes.

Risk factors:
Anyone can get pityriasis rosea, but it is more common in older children and young adults (10 – 35 years old).

  • Some people feel unwell for a day or two before they get the rash, with flu-like symptoms, such as: a sore throat and swollen lymph nodes in the neck.
  • The onset of a large patch on the skin. This is usually the first sign of pityriasis rosea (a herald patch). It is a pink or red patch of scaly skin, ranging in size from 2 to 10 cm. The rash appears on the abdomen, chest, or back. It can also develop anywhere on the skin, including the armpits.
  • The color of the patch in fair-skinned people is usually red or pink. As for people with a darker skin, the spots can sometimes be gray, dark brown, or black.

Other symptoms that are likely to develop include:
  • Feeling unwell
  • Headache
  • Fever
  • Loss of appetite 
  • Nausea
  • Sleep disruption

When to see a doctor?
  • If you develop a persistent unexplained rash. Your doctor should be able to tell if the rash is the result of pityriasis rosea or other skin conditions like: eczema, psoriasis, or ringworm;
  • If the patient is pregnant;
  • If the rash persists for over 3 months;
  • If the itching or other symptoms remain as they are or get worse 2 months after developing the rash.

Complications of pityriasis rosea are unlikely. However, if a pregnant woman gets it, she must see her doctor immediately.

In most cases, a doctor can recognize pityriasis rosea just by looking at the rash. He or she may want to take a swab of the rash or ask that the patient for a blood test to rule out any conditions similar to pityriasis rosea, such as ringworm. Moreover, some medications can cause a rash that looks like pityriasis rosea, so it is important to rule this possibility out.

Pityriasis rosea usually disappears within 6 to 8 weeks. In some cases, though, it can last up to 5 months, but treatment is not required unless it causes severe itching or fatigue. The treatment may include the following:
  • Treatments to reduce skin itch under the supervision of a doctor. They include anti-itch lotions or creams, such as a hydrocortisone cream, in addition to antihistamines.   
  • Ultraviolet light therapy (provided at a dermatologist's clinic).
  • As soon as the rash disappears, dark spots may appear, especially in dark-skinned people. These spots usually disappear on their own within 6 to 12 months.

The cause of pityriasis rosea is still unknown, so there are no specific ways to prevent it.

  • Is pityriasis rosea contagious?
    • While more than one person in a family may develop this rash at the same time, pityriasis rosea is not contagious and does not spread from one person to another.
  • Is there a link between pityriasis rosea and human herpes?
    • Dermatologists have found human herpes viruses in the rashes, blood, and saliva of people with pityriasis rosea. However, strains of human herpes viruses cannot cause cold sores or genital herpes, and when a person is infected with them, they remain inside the body. They do not cause any problems because the immune system keeps them under control.
  • If I get pityriasis rosea once, will I get it again?
    • Many people get pityriasis rosea only once without having it again; however, it is possible to get the rash more than once. 

Myths & Truths:
  • Pityriasis rosea is the same as ringworm. 
    • Truth: Ringworm is a common fungal infection of the skin. The spots resulting from ringworm are lighter than the color of the skin and appear on the shoulders and back. On the other hand, the cause of pityriasis rosea is unknown. It is believed, however, to be a viral infection. It starts with a red or pink spot on the abdomen, chest, back, or neck.

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Last Update : 22 September 2021 01:01 AM
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