II. Epidemiology
- Incidence: 170 per 100,000 persons/year
- Ages 10 to 50 years (peaks age 20 to 30 years)
- No gender predisposition
- Seasonal variation: more common in spring and fall
- Higher risk in pregnancy (RR 3)
- Associated with increased Miscarriage rate before 15 weeks gestation (see below)
III. Pathophysiology
- Papulosquamous eruption
- Thought to be of infectious etiology (Viral Exanthem)
- May be associated with reactivation of Human Herpes Virus 6 (Roseola Infantum, HHV-6) or HHV-7
- Campolat (2009) J Eur Acad Dermatol Venereol 23(1): 16-21 [PubMed]
IV. Symptoms
- Moderate to Severe Pruritus (25-50% of cases)
- Especially in children
- Other symptoms present in only 5% of patients
- Viral prodrome-type constitutional symptoms may occur with mild URI symptoms
- Headache
- Malaise
- Arthralgias
- Chills
- Nervousness
- Gastrointestinal symptoms
V. Signs
- Herald Patch (initial presenting lesion in 80-90% of patients)
- Single oval Macule or patch on trunk
- Diameter: 2 to 10 cm
- Characteristics: Annular Lesion (oval)
- Erythematous (rose colored) border with fine peripheral scale
- Central clearing
- Christmas tree pattern rash
- Onset occurs 7-14 days after herald patch
- Lesions may continue to appear for up to 6 weeks after onset
- Symmetric bilaterally
- Smaller than herald patch (<1 cm)
- Rash follows skin Cleavage Lines (Langer Lines)
- Christmas-Tree distribution on back
- V-Shaped distribution on the chest
- Individual lesions appear similar to herald patch
- Small fawn or salmon colored oval Macules
- Peripheral scaly collarettes
- Central clearing
- Darker skin: Black Children
- More facial (30% of cases) and scalp involvement
- Post-inflammatory pigment changes take place in nearly two thirds of patients
- Variants: Atypical Pityriasis Rosea
- Pityriasis Rosea Gigantea of Darier
- Fewer, but larger lesions
- Inverse Pityriasis Rosea
- Lesions primarily involve face, axilla, groin
- Pityriasis Rosea of Vidal
- Large patches involve the axillae or inguinal region
- Pityriasis Rosea Gigantea of Darier
VI. Differential Diagnosis: Medical Conditions
- See Annular Lesion
- Viral Exanthem
- Seborrheic Dermatitis
-
Secondary Syphilis
- Unlike pityriasis, Syphilis affects palms and soles
- Nummular Eczema
-
Tinea Corporis
- Typically a single lesion (may be confused with herald patch)
- Once Christmas Tree pattern of lesions develops, Pityriasis diagnosis becomes more obvious
- Guttate Psoriasis
- Lichen Planus
VII. Associated Conditions: Medications associated with Pityriasis Rosea Eruptions
- Adalimumab (Humira)
- Allopurinol
- Arsenic
- Asenaprine
- Atenolol
- Barbiturates
- BCG vaccine
- Bismuth
- Bupropion
- Captopril
- Clonidine
- Clozapine
- Ergotamine
- Gold
- Hepatitis B Vaccine
- Imatinib (Gleevec)
- Interferon alfa
- Influenza Vaccine
- Isotretinoin
- Ketotifen
- Lamotrigine (Lamictal)
- Lisinopril
- Nortriptyline
- Omeprazole (Prilosec)
- Pneumovax Vaccine
- Rituximab
- Smallpox Vaccine
- Terbinafine
- Yellow Fever Vaccine
VIII. Labs
- Syphilis Serology (RPR)
- Skin biopsy for direct fluorescent Antibody
- Indicated only if Syphilis strongly considered
- Pityriasis Rosea will show dyskeratotic degeneration
IX. Management (No effective treatment)
- Severe Pruritus
- See Pruritus Management
- Topical Corticosteroid
- Oral Antihistamine
- Calamine lotion or Zinc Oxide
- Severe Cases
- Ultraviolet A Light
- Ultraviolet B Light
- Systemic Corticosteroids
- Acyclovir
- Adult standard dosing: 800 mg orally five times daily for 7 days (400 mg may also be effective)
- Disproven treatments
- Macrolides (e.g. Erythromycin) are now not thought to be effective
X. Complications
- Associated with Miscarriage (57%) when presents in the first 15 weeks of pregnancy
XI. Course
- Spontaneous resolution within 6 to 8 weeks in 80% cases (range 2-12 weeks duration)
- Recurrence in less than 3%
XII. References
- Allen (1995) Cutis 56:198-202 [PubMed]
- Allmon (2015) Am Fam Physician 92(3): 211-6 [PubMed]
- Chuh (2016) J Eur Acad Dermatol Venereol 30(10): 1670-81 [PubMed]
- Hsu (2001) Am Fam Physician 64(2):289-96 [PubMed]
- Kempf (2000) Arch Virol 154(8):1509-20 [PubMed]
- Stulberg (2004) Am Fam Physician 69:97-94 [PubMed]