Diagnosis: Pityriasis lichenoides
Description: This shows the stuck on mica like scale
Morphology: Red,scaly
Site: Arm,forearm
Sex: M
Age: 34
Type: Clinical
Submitted By: Ian McColl
Differential DiagnosisHistory:
Pityriasis lichenoides comes in an acute and chronic form.It probably is a reaction to a viral infection in the skin but it takes a considerable time to settle.Clinically it resembles guttate psoriasis or secondary syphilis but it may show the characteristic mica or stuck on scale.Ultraviolet light is the most effective treatment to speed up resolution of the condition.
There is an acute form called PLEVA which is more papular and sometimes shows crusting and necrosis of the lesions.It is more likely to scar.