Pityriasis lichenoides

Definition

Pityriasis lichenoides is an uncommon inflammatory skin disease of unknown aetiology. It can range from a relatively mild chronic form to a fulminant form with skin necrosis and severe constitutional symptoms. The disease can last from just weeks to months or years. The chronic form is manifest as multiple small flat asymptomatic scaly papules located predominantly on the trunk and proximal limbs. The acute forms present with the abrupt appearance of multiple papules in the same distribution which rapidly progress to haemorrhagic blisters and ulceration.

Inclusions

• Pityriasis lichenoides chronica
• Pityriasis lichenoides et varioliformis acuta
• Febrile ulceronecrotic Mucha-Habermann disease

Index Terms