Pityriasis Rosea: Clinical Features, Diagnosis, and Management
Pityriasis rosea is a common, self-limited papulosquamous dermatosis characterized by a herald patch followed by a generalized eruption that typically resolves within 6-8 weeks without treatment. 1
Clinical Presentation
Key Features
- Herald patch: Present in approximately 80% of cases, this larger (2-10 cm), solitary, oval or round erythematous patch with a collarette of scale appears first, typically on the trunk 1
- Secondary eruption: Develops 4-14 days after the herald patch, consisting of multiple smaller (0.5-1 cm) oval or elliptical salmon-colored macules with peripheral scaling 1
- Distribution pattern:
- Lesions follow Langer's lines of cleavage (skin tension lines)
- "Christmas tree" pattern on the back
- V-shaped pattern on the upper chest 1
- Age distribution: Primarily affects individuals between 10-35 years, with peak incidence during adolescence 1
Prodromal Symptoms
- Present in approximately 5% of patients
- May include headaches, fever, malaise, fatigue, anorexia, sore throat, lymphadenopathy, and arthralgia 1
Etiology
- Human herpesvirus (HHV)-7 and HHV-6 have been implicated as causative agents in some patients 1, 2
- The disease is associated with endogenous systemic reactivation of these viruses 2
Atypical Presentations
- Unilateral distribution (rare) 3
- Herald patch as the only manifestation (abortive form) 2
- Erythema multiforme-like lesions 4
- Absence of herald patch
- Variations in size, distribution, and morphology of lesions
Diagnosis
Diagnosis is primarily clinical, based on:
- Presence of herald patch
- Characteristic distribution and morphology of secondary eruption
- Typical time course
Differential Diagnosis
- Secondary syphilis
- Seborrheic dermatitis
- Nummular eczema
- Pityriasis lichenoides chronica
- Tinea corporis
- Viral exanthems
- Lichen planus
- Drug eruptions 5
Diagnostic Challenges
- Atypical presentations may pose diagnostic difficulties
- Consider skin biopsy for atypical eruptions without a definite diagnosis 3
Management
General Approach
- Reassurance about the self-limiting nature of the condition
- Symptomatic treatment for pruritus if present 1
Specific Treatments
For severe, recurrent cases or pregnant women with the disease:
- Oral acyclovir: Evidence supports its use to shorten disease duration 1, 5
- Macrolides: Particularly erythromycin may be beneficial 1
- Symptomatic relief:
- Antihistamines for pruritus
- Topical corticosteroids for inflammation 5
- Ultraviolet phototherapy: Consider for severe cases 1, 5
Special Considerations
Pregnancy
- Pityriasis rosea during pregnancy has been associated with spontaneous abortions 5
- More aggressive treatment may be warranted in pregnant women
Course and Prognosis
- Typical duration: 6-8 weeks
- Self-limiting in the vast majority of cases
- Recurrence is uncommon 1
Follow-up
- Regular follow-up may be necessary for atypical presentations
- Consider reassessment if symptoms worsen or fail to improve within the expected timeframe
By understanding the typical and atypical presentations of pityriasis rosea, clinicians can make accurate diagnoses and provide appropriate reassurance and management to affected patients.