Introduction
Epidemiology
- Incidence: 5.00 cases per 100,000 person-years
- Peak incidence: 30-40 years
- Sex ratio: 1:1
Condition | Relative incidence |
---|---|
Pityriasis rosea | 34.00 |
Guttate psoriasis | 1 |
<1 | 1-5 | 6+ | 16+ | 30+ | 40+ | 50+ | 60+ | 70+ | 80+ |
Clinical features
Differential diagnosis
Guttate psoriasis | Pityriasis rosea | |
---|---|---|
Prodrome | Classically preceded by a streptococcal sore throat 2-4 weeks | Many patients report recent respiratory tract infections but this is not common in questions |
Appearance | 'Tear drop', scaly papules on the trunk and limbs | Herald patch followed 1-2 weeks later by multiple erythematous, slightly raised oval lesions with a fine scale confined to the outer aspects of the lesions. May follow a characteristic distribution with the longitudinal diameters of the oval lesions running parallel to the line of Langer. This may produce a 'fir-tree' appearance |
Treatment / natural history | Most cases resolve spontaneously within 2-3 months Topical agents as per psoriasis UVB phototherapy | Self-limiting, resolves after around 6 weeks |
Management
- most cases resolve spontaneously within 2-3 months
- there is no firm evidence to support the use of antibiotics to eradicate streptococcal infection
- topical agents as per psoriasis
- UVB phototherapy
- tonsillectomy may be necessary with recurrent episodes