Addison's disease (hypoadrenocorticism) causes potentially fatal adrenal crises but can be managed long-term with medication, allowing affected dogs to live full, comfortable lives.
Addison's disease causes profound welfare impacts before diagnosis - affected dogs experience episodes of severe weakness, nausea, and potential cardiovascular collapse that are terrifying and physically devastating. The diagnostic delay is common because symptoms are vague and episodic. Once diagnosed and appropriately treated, the welfare transformation is dramatic - dogs that were periodically collapsed resume normal, active lives. The ongoing welfare consideration is stress-related crises - during illness, surgery, or extreme stress, additional corticosteroid supplementation is required to prevent Addisonian crisis.