Pityriasis rosea

Overview:

• Self-limiting rash seen in adolescents and young adults
• Unknown cause but is thought to be a viral or post-viral rash

Clinical features:

• The rash consists of circular or oval pink macules with a collarette of scale
• Is more prominent on the trunk than on the limbs
• The long axis of the oval lesions tends to run along dermatomal lines, giving a ‘Christmas tree’ pattern on the back
• The rash may be preceded by a large solitary patch with peripheral scaling (‘herald patch’) and this is most commonly found on the trunk
• Is usually asymptomatic
• Spontaneously resolves over 4-8 weeks

Treatment:

• Not normally required
• 0.5% menthol in aqueous cream may help relieve the itching
• In persistent cases, UVB may be helpful