Pityriasis rosea is a self-limiting skin disorder characterized by a solitary oval-shaped herald patch followed by smaller erythematous papulosquamous lesions in a characteristic ‘Christmas tree’ distribution along Langer lines. It is associated with HHV-6 and HHV-7 reactivation.
Pityriasis rosea vs Guttate psoriasis
| Pityriasis rosea | Guttate psoriasis | |
|---|---|---|
| Prodrome | Recent respiratory tract infection | Preceded by streptococcal sore throat by 2 – 4 weeks |
| Apeparance | Herald patch followed by multiple, erythematous, slightly raised oval lesions | ‘Tear drp’ scaly papules on the trunk and limbs |
| Treatment | Self-limiting, resolves within 6 weeks | Resolves within 2 – 3 months, topical agents can be used as per psoriasis, UVB phototherapy |
- Signs and symptoms
- Prodromal viral symptoms such as malaise, nausea, fever, joint pains, and headache
- Severe pruritus
- Herald patch is usually on the trunk
- Erythematous, oval scaly patches with the longitudinal diameters running parallel to Langer lines; this produces a ‘Christmas-tree’ appearance
- Differentials
- Drug rash
- Urticaria
- Guttate psoriasis
- Tinea corporis
- Erythema multiforme
- Pityriasis versicolour
- Lichen planus
- Secondary syphilis
- Treatment
- Self-limiting with an excellent prognosis: it resolves within 6 weeks
- Topical corticosteroids to reduce inflammation and itching
- Emollients to relieve itching
- Antihistamines to relieve itching at night
- UV therapy for severe or persistent cases
- Complications
- Post-inflammatory hyperpigmentation or hyperpigmentation
- Miscarriage, preterm labor, or low birth weight if it occurs in pregnancy
