IL-1β concentration in the BF was correlated with the skin erythema/urticaria activity (n = 25; r = 0.55; p = 0.0048; Figure 2D), but neither with the total BPDAI score (n = 25; r = 0.29; p = 0.15; Figure 2B), nor with the skin BPDAI subscore associated with blisters and erosions (n = 25; r = 0.11; p = 0.62; Figure 2C). Here, IL1B is linked to Erythema.