Segmental lesions in pityriasis rosea: a rare presentation

Area of Science:

• Dermatology
• Clinical Case Study
• Infectious Disease

Background:

• Pityriasis rosea (PR) is an acute, self-limiting skin condition of unknown etiology, typically presenting with a herald patch followed by a generalized eruption.
• While commonly affecting the trunk and proximal extremities, atypical presentations can occur, posing diagnostic challenges.

Observation:

• A 34-year-old woman presented with a pruritic breast lesion, initially unresponsive to antifungal cream.
• The eruption evolved into multiple oval, scaly plaques on the chest and back, following a dermatomal distribution (T4), with characteristic peripheral collarette scaling.
• Systemic examination, blood work, and serological tests (VDRL, HIV) were unremarkable. Fungal studies were negative.

Findings:

• The clinical presentation, despite the unusual location and initial atypical features, was consistent with pityriasis rosea.
• The patient experienced complete resolution of the rash with topical corticosteroids and oral antihistamines.
• No recurrence was noted one year post-treatment, supporting the diagnosis.

Implications:

• This case underscores the importance of considering pityriasis rosea in the differential diagnosis of breast and chest wall eruptions, even with atypical features.
• Dermatomal distribution and peripheral collarette scaling can be key diagnostic clues in challenging cases.
• Successful management with symptomatic treatment highlights the self-limiting nature of pityriasis rosea.