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Patient Case: Pityriasis Rosea

Patient Case: Pityriasis Rosea

Discussion

A 22-year-old woman presents to the dermatology clinic with a two-week history of a widespread, mildly itchy rash that began on her trunk. She reports that about a week before the rash appeared, she noticed a single, oval-shaped, scaly pink patch on her abdomen, which she initially thought was a fungal infection. A few days later, multiple smaller, similar lesions appeared on her chest, back, and upper arms. She denies fever, sore throat, or other systemic symptoms.

On examination, there is a large, well-defined, scaly, pink plaque (herald patch) on the lower abdomen, along with multiple smaller, scaly, oval papules and plaques arranged along the skin folds in a "Christmas tree" pattern on the back. The lesions are not painful, and there is no mucosal involvement.

A diagnosis of pityriasis rosea is made. The patient is reassured that the condition is self-limiting and is advised to use moisturizers, antihistamines for itching, and mild topical steroids if needed. She is informed that the rash may last 6 to 8 weeks but will resolve without scarring.

Questions
  1. What is the most likely diagnosis for this patient’s condition?
    a) Tinea corporis
    b) Pityriasis rosea
    c) Psoriasis
    d) Secondary syphilis
  2. What is the characteristic initial lesion seen in pityriasis rosea?
    a) Herald patch
    b) Bullous blister
    c) Target lesion
    d) Vesicular rash
  3. Which of the following best describes the distribution pattern of pityriasis rosea?
    a) Linear streaks along the arms and legs
    b) Butterfly-shaped rash on the face
    c) Christmas tree pattern on the trunk
    d) Confluent erythema on the palms and soles
  4. What is the best management approach for pityriasis rosea?
    a) Oral antifungals
    b) Topical corticosteroids and antihistamines for symptom relief
    c) Systemic antibiotics
    d) Phototherapy as the first-line treatment
Reveal answers

Answers

  1. (b) Pityriasis rosea
    • The presence of a herald patch followed by a widespread, scaly rash in a Christmas tree pattern is typical of pityriasis rosea, a self-limiting viral exanthem.
  2. (a) Herald patch
    • The herald patch is a single, well-defined, oval pink lesion with fine scaling, which appears before the generalized rash in pityriasis rosea.
  3. (c) Christmas tree pattern on the trunk
    • The secondary rash in pityriasis rosea follows Langer’s lines, forming a Christmas tree-like distribution on the back.
  4. (b) Topical corticosteroids and antihistamines for symptom relief
    • Pityriasis rosea is self-limiting and does not require aggressive treatment. Moisturizers, antihistamines, and mild corticosteroids help relieve itching.