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Integumentary system ORGAN SYSTEMS

Pityriasis rosea

Pityriasis rosea is an acute, self-limited eruption of oval, scaly papules and plaques with a distinctive morphology. Females are affected more often than males, and it most common in teenagers and young adults. Pityriasis rosea peaks in the spring and fall seasons. The most probable cause has been attributed to reactivation of human herpesvirus (HHV-6 and HHV-7). | Pityriasis Rosea: Jorge Muniz, PA-C

Christmas tree rash, or pityriasis rosea, is an acute, self-limiting, papulosquamous eruption with a duration of 6-8 weeks.

  • Non-contageous

Aetiology

Associated with:

  • Human herpesvirus 6 (HHV6) or human herpesvirus 7 (HHV7)

Clinical features

URTI precedes all other symptoms (69% cases)

  • Single, 2-10-cm oval red “herald” patch
    • Appears on abdomen (classically) or in ‘hidden’ positions (in the armpit, for example)
    • May also appear as a cluster of smaller oval spots, and be mistaken for acne (D/D)
  • 7–14 days after the herald patch,
    • Many small (5–10 mm) patches of pink/red, flaky, oval-shaped rash appear on the torso.
    • “Christmas-tree” distribution
      • Spread widely across the chest first, following the rib-line
  • Small, circular patches may appear on the back and neck several days later.

Diagnosis

Clinical diagnosis

A patient is diagnosed as having pityriasis rosea if:

  1. On at least 1 occasion/clinical encounter, he/she has all essential + atleast 1 optional clinical features
  2. On all occasions/clinical encounters related to rash, he/she does not have any of the exclusional clinical features.

The essential clinical features are the following:

  1. Discrete circular or oval lesions,
  2. Scaling on most lesions, and
  3. Peripheral collarette scaling with central clearance on at least 2 lesions.

The optional clinical features are the following:

  1. Truncal and proximal limb distribution, (< 10% of lesions distal to mid-upper-arm and mid-thigh),
  2. Orientation of most lesions along skin cleavage lines, and
  3. A herald patch (not necessarily the largest) appearing at least 2 days before eruption of other lesions, from history of the patient or from clinical observation.

The exclusional clinical features are the following:

  1. Multiple small vesicles at the centre of two or more lesions,
  2. ≥ 2 lesions on palmar/plantar skin surfaces, and
  3. Clinical/serological evidence of secondary syphilis.

Management

Condition usually resolves on its own, and treatment is not required.

Supportive therapy:

  • Sunlight/UVB-phototherapy
    • Help the lesions disappear faster if started during the first week of eruption
  • Itching:
    • Lotions, oral antihistamines, and/or topical glucocorticoids

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