From the Guidelines
Blanching erythema and non-blanching erythema are distinguished by their response to pressure, with blanching erythema temporarily disappearing with pressure and non-blanching erythema persisting, indicating potentially more serious underlying conditions. The key difference between blanching (transient) erythema and non-blanching (persistent) erythema lies in their response to applied pressure and the underlying causes of the erythema. Blanching erythema is characterized by redness of the skin that temporarily disappears when pressure is applied, such as with a glass slide or finger, and then returns when the pressure is released 1. This phenomenon occurs because the pressure temporarily forces blood out of the dilated capillaries, and the erythema typically indicates inflammation, sunburn, or other processes that cause vasodilation but maintain intact blood vessels. In contrast, non-blanching (persistent) erythema does not disappear with pressure because the redness results from blood that has leaked outside the vessels into surrounding tissues. Non-blanching erythema is characteristic of more serious conditions like purpura, petechiae, or hemorrhage, often indicating vessel damage, bleeding disorders, or severe infections like meningococcemia 1. This distinction is clinically important as non-blanching rashes generally suggest more serious underlying pathology requiring urgent evaluation, while blanching erythema typically represents more benign inflammatory processes. Some studies have discussed the importance of differentiating between these types of erythema in the context of rosacea and other skin conditions, emphasizing the need for accurate diagnosis and appropriate management 1. The diascopy test (pressing a glass slide against the skin) is a simple bedside examination that can help differentiate between these two types of erythema. It is essential to recognize the differences between blanching and non-blanching erythema to provide appropriate care and management for patients presenting with these conditions. In clinical practice, understanding the distinction between blanching and non-blanching erythema can significantly impact patient outcomes, particularly in terms of morbidity, mortality, and quality of life. Therefore, healthcare professionals should prioritize the identification and differentiation of these two types of erythema to ensure timely and effective treatment.
From the Research
Definition of Blanching and Non-Blanching Erythema
- Blanching erythema is a type of skin discoloration that fades when pressed, indicating normal blood flow to the area 2.
- Non-blanching erythema, on the other hand, is a type of skin discoloration that does not fade when pressed, suggesting impaired blood flow to the area 3, 2, 4.
Characteristics of Non-Blanching Erythema
- Non-blanching erythema is often characterized by petechial dots, telangiectatic streaks, and purpura that persist after compression by a dermoscope 4.
- It is a common indicator of stage I pressure ulcers and is prone to develop into more severe pressure ulcers if left untreated 3, 5.
Difference between Blanching and Non-Blanching Erythema
- Blanching erythema is associated with high blood flow, whereas non-blanching erythema is associated with altered blood perfusion and impaired blood flow 3, 2.
- Non-blanching erythema is a more severe condition that requires prompt attention and preventive measures to prevent further deterioration 5, 6.
Predictive Value of Blanching Erythema
- Blanching erythema has a predictive accuracy for pressure ulcer development, with a sensitivity of 75%, specificity of 77%, and positive likelihood ratio of 3.26 6.
- However, the positive likelihood ratio has a small effect on clinical use, and adequate support surface management can reduce the incidence of pressure ulcers in patients with blanching erythema 6.