Prerequisite: Time Lord
The Time Lord picked up an allergy during their last regeneration that seriously sickens and might even kill them, like certain gases or even something as harmless as aspirin. This is usually caused by exposure to or contact with some rare element that is incorporated into the body during regeneration and is typically only seen in field agents or renegades who insist on mucking about in the relatively unhygienic universe outside of Gallifrey.
The GM picks a substance. It should be common enough that it could be encountered occasionally (like ammonia or aspirin), but not so common that the Time Lord is endangered every time they step out of the TARDIS (like rock quarries).
As a Minor Trait, the substance causes 1 point of damage for every round that the Time Lord is exposed to it.
As a Major Bad Trait, the substance does D6 damage per round of exposure.
As a Special Bad Trait, you gain 1 Story Point, but the substance is Lethal to the Time Lord. This Trait may be taken more than once.