Pityriasis rosea

What is Pityriasis rosea?

It is a harmless single, large skin rash that causes severe discomfort. It was first described by Gilbert in 1860. The common skin disorder normally refers to “fine pink scale”. It is also called pityriasis rosea of Gilbert.

Pityriasis rosea Epidemiology/Incidence

The rate of incidence is higher in females than males. It is common in children and young adults between the ages of 10 and 35. The condition is notable in few African Americans even though it has no racial predominance.

Pityriasis rosea

Pityriasis rosea Symptoms

It usually begins as a single, oval red rash on the trunk/torso, particularly the abdomen and genitals, called “herald patch” or “mother patch”. The lesions may measure between 2 and 10 cm. In some cases, the herald patch may apparently look like a cluster of smaller oval spots, similar to acne. In about 7-14 days, the large rash is replaced with smaller patches, measuring 5-10 mm, in a “Christmas tree” formation with the long axis of the ovals oriented in the “Lines of Blaschko”, along the rib-line, that lasts up to 12 weeks. Therefore, these oval macules are more obvious across the chest. In a short period of time, the minute lesions spread to the neck and back. Although the face is devoid of any such rashes, some patients may develop the condition on the cheeks or at the lower edges of the hair. In few instances, the upper and lower extremities are severely affected by the skin ailment. Sometimes, it is difficult to make out the condition if the rash occurs in the armpits and groin.

Sufferers may experience mild to severe itching that aggravates when scratched or pricked. As the affected skin is prone to dryness, pruritis is a common sign of the disorder. Strenuous work outs, stress or hot showers can trigger the problem. However, it may take 6-8 weeks for the problem to clear completely. According to medical experts, the condition is asymptomatic except for the appearance of the characteristic rash. Most patients suffer from an upper respiratory tract infection prior to the development of the benign rash. For this reason, the condition mimics well-known fungal infections and produce flu-like symptoms such as:

  • Headache
  • Fever
  • Chills
  • Sore throat
  • Fatigue
  • Nausea
  • Body ache
  • Joint pain
  • Loss of appetite
  • Oral blisters or ulcers

Pityriasis rosea Causes

The condition has an unknown etiology despite the significant dermatologic signs. Howbeit, the recent cases of pityriasis rosea of Gilbert have been linked with Human herpesvirus 7, one of the eight known members of the Herpesviridae family. It is not a result of genital or oral herpes as the manifestations are quite different. It could be contagious, but gets transmitted only through respiratory contact. Hence, close or direct exposure to the rash does not lead to the condition.

Pityriasis rosea Diagnosis

The large herald patch followed by the symmetrical Christmas tree pattern on the trunk is suggestive of an underlying viral infection. The scaly patches have fine borders unlike the other cutaneous disorders. A skin biopsy is mandatory to identify the type of rash affecting the skin. A series of blood tests are conducted for antibodies of Human herpesvirus 7. Potassium hydroxide test is a spontaneous technique to detect the presence of fungal infections. The following criteria normally help healthcare advisors to diagnose the condition:

  • Distinct oval macules
  • Scaly patches covering the lesions
  • Circumferential collarette scaling with central clearance
  • Truncal and proximal distribution
  • Presence of multiple tiny vesicles in the lesions

Pityriasis rosea Histopathology

The condition develops as a result of decreased natural killer cells and B-cell activity in the lesions. Viral antigens abruptly raise the amount of CD4 T cells and Langerhans cells in the dermis. Biopsies represent extravasated erythrocytes within dermal papillae, and dyskeratotic cells within the dermis.

Pityriasis rosea Differential Diagnosis

Pityriasis rosea on black people

It is highly essential to isolate the signs of the condition from other skin ailments. These may include:

  • Viral exanthemas
  • Pityriasis amiantacea
  • Subacute cutaneous lupus erythematosus
  • Cutaneous T-cell lymphoma
  • Lyme disease
  • Ringworm
  • Nummular or discoid eczema
  • Drug eruptions
  • Guttate psoriasis
  • Syphilis
  • Tinea versicolor

Pityriasis rosea Treatment

The condition is self-limiting and does not require any treatment. The itchy rash in most patients resolves within 2-3 months without any therapeutic aid. However, additional care is needed during pregnancy. Use of topical steroid creams, such as hydrocortisones, and oral histamines like diphenhydramine and loratidine mitigates the frequent episodes of itching. However, these medications do not clear the rash spontaneously. Direct exposure of the affected skin to UVB light or sunlight could prove to be beneficial since these accelerate the process of alleviation. Off-label use of erythromycin or anti-viral drugs, such as acyclovir or famciclovir, could reduce the condition. In addition to these, patients should take the following precautionary measures:

  • Avoid the use of drying soaps, wool, synthetic cloths, and lukewarm water
  • Moisturizers with goat’s milk as an important ingredient should be applied over the rash
  • Application of ketoconazole-containing shampoos on the affected scalp
  • Avoid scratching in order to prevent the development of another itch-scratch cycle
  • Regular hand washing

Pityriasis rosea Natural/Home remedies

Natural therapeutic interventions are quite safe for the resolution of the rash. In such cases, Ayurvedic herbal remedies could help in the removal of the lesions. These generally include:

  • Oatmeal baths
  • Calamine or menthol lotions
  • Zinc oxide creams
  • Consumption of Benadryl oral pills or liquids

Pityriasis rosea Prognosis

As aforementioned, the condition does not last for more than 3 months and does cause any kind of scarring or hypopigmentation post resolution of the lesions. It normally induces lifelong immunity after one episode. It rarely recurs in the lifetime of the patients.

Pityriasis rosea Pictures






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