Question: What causes Alopecia universalis ?
Answer: What causes alopecia universalis? The exact underlying cause of alopecia universalis (AU) is not currently known. AU is an advanced form of alopecia areata (AA), a condition that leads to round patches of hair loss. AA is thought to be an autoimmune condition in which an affected person's immune system mistakenly attacks the hair follicles. Genetic studies have found that AA and AU are associated with several immune-related genes; however, they are likely complex disorders caused by the interaction of multiple genetic and environmental factors. This means that even if someone inherits a genetic predisposition to the condition, they may not become affected unless something in the environment triggers the onset of the condition.
Source: GARD