Halruaan Consumption was a deadly, magical wasting disease that could be contracted by non-spellscared creatures who ventured into the wastelands of Halruaa in the years following the Spellplague, and until the return of Halruaa as part of the Second Sundering, when most of the effects of the Spellplague ended.
In the initial stages of the disease any healing spells cast on the afflicted creature would be less effective. However, arcane attack spells cast by the creature would be more powerful. Some victims recovered spontaneously in the early stages and acquired a spellscar. If a victim didn't recover and the disease progressed, the victim would suffer damage to his body. In the terminal stage the afflicted disintegrated into luminous blue dust.