Hypersensitivity angiitis

This code represents a systemic vasculitis characterized by inflammation and necrosis of small blood vessels, often triggered by an allergic or hypersensitivity reaction to drugs, infections, or other foreign substances. It primarily affects postcapillary venules and can manifest with skin lesions (e.g., palpable purpura), arthralgias, and renal involvement.

Use this code for patients diagnosed with hypersensitivity angiitis, also known as cutaneous leukocytoclastic vasculitis, when the underlying cause is an identifiable hypersensitivity reaction. Documentation should clearly indicate the diagnosis of hypersensitivity angiitis and ideally, the suspected trigger.

• Differentiate from other forms of vasculitis; this code specifically denotes hypersensitivity as the etiology.
• Ensure documentation supports the "angiitis" component, indicating inflammation of blood vessels, not just a skin reaction.
• Consider sequencing this code as a primary diagnosis when it is the main reason for the encounter, or as a secondary diagnosis when it is a manifestation of another underlying condition.