Reticulate eruptions: Part 2. Historical perspectives, morphology, terminology and classification

Area of Science:

• Dermatology
• Vascular Biology
• Pathology

Background:

• Reticulate eruptions signal diverse vascular pathologies, including arterial, venous, microvascular, or combined issues.
• Patterns like stellate, reticulate, and racemosa are linked to specific vascular origins and clinical presentations.
• 'Livedo' describes skin discoloration, not the eruption pattern itself.

Purpose of the Study:

• To elucidate the vascular origins and characteristic patterns of reticulate eruptions.
• To differentiate between physiological and pathological causes of livedo reticularis and livedo racemosa.
• To highlight the diagnostic significance of retiform purpura in thrombohemorrhagic conditions.

Main Methods:

• Clinical observation and pattern analysis of reticulate eruptions.
• Correlation of eruption morphology with underlying arterial, venous, or microvascular pathology.
• Differentiation of primary livedo reticularis from secondary causes and pathological livedo racemosa.

Main Results:

• Arterial pathology presents as stellate patterns with blanched centers, while venous pathology shows reticulate or racemosa configurations.
• Primary livedo reticularis (cutis marmorata) is a blanchable response to cold, whereas livedo racemosa is non-blanchable and pathological.
• Retiform purpura signifies inflammatory or thrombohemorrhagic processes, including disseminated intravascular coagulopathy.

Conclusions:

• Reticulate eruption patterns are crucial indicators of underlying vascular disease.
• Distinguishing between blanchable and non-blanchable livedo patterns is essential for diagnosis.
• Retiform purpura warrants investigation for severe systemic conditions like disseminated intravascular coagulopathy.