Hypothalamo-Pituitary Axis Suppression (HPAAS) is a condition where the HPA axis becomes underactive or dysfunctional, leading to an impaired ability to respond effectively to stressors. This suppression can result in various health issues, including late-onset bullous ENL. The condition is often associated with long-term use of exogenous corticosteroids, such as prednisolone, which can lead to HPAAS. The suppression of the HPA axis can result in an inadequate amount of endogenous steroid being produced, which may trigger late-onset bullous ENL.