Retiform purpura

Retiform purpura is a distinctive pattern of purpura characterized by a net-like, branching, or reticulated pattern. This condition is a clinical manifestation rather than a specific disease, indicating underlying pathology that may involve the vasculature of the skin. Retiform purpura can be a sign of various conditions, including vasculitis, coagulopathies, and embolic phenomena, making its diagnosis and management critical for clinicians.

Etiology

Retiform purpura arises from occlusion of the dermal vessels, which can result from a variety of causes. These include:

• Vasculitis: Inflammation of the blood vessels can lead to occlusion and subsequent purpura. Examples include Henoch-Schönlein purpura, cryoglobulinemia, and septic vasculitis.
• Coagulopathies: Disorders of the coagulation system, such as disseminated intravascular coagulation (DIC) or antiphospholipid syndrome, can lead to vascular occlusion and retiform purpura.
• Embolic phenomena: Emboli, or clots that travel through the bloodstream and lodge in small vessels, can cause this pattern of purpura. Sources of emboli include endocarditis and cholesterol emboli syndrome.

Clinical Presentation

Patients with retiform purpura typically present with reddish-purple, branched, or net-like patterns on the skin. These lesions are non-blanching, meaning they do not turn white when pressure is applied, indicating that the discoloration is due to bleeding under the skin rather than inflammation or infection. The lesions can be localized or widespread, depending on the underlying cause.

Diagnosis

The diagnosis of retiform purpura involves a thorough history and physical examination, followed by targeted laboratory and imaging studies to identify the underlying cause. Tests may include:

• Complete blood count (CBC)
• Coagulation profile
• Antinuclear antibody (ANA) test
• Cryoglobulins
• Skin biopsy: A biopsy of the affected skin can provide crucial information about the nature of the vessel occlusion and the presence of vasculitis or other pathology.

Treatment

Treatment of retiform purpura focuses on addressing the underlying cause. This may involve:

• Corticosteroids or other immunosuppressive agents for vasculitis
• Anticoagulants for coagulopathies
• Antibiotics for infectious causes
• Supportive care, including wound care for skin lesions

Prognosis

The prognosis of retiform purpura varies widely depending on the underlying cause. Early diagnosis and treatment are crucial for improving outcomes, especially in cases where the condition is a manifestation of a life-threatening disease.