What are the most lucrative part time jobs? Either unskilled or something you could blag your way into with the relevant experience and references from Vandelay Industries.
The best I've found after 5 minutes of dicking around on Indeed is being a kitchen porter for £15 an hour.
In a Phase I trial of a new drug, any allergies are immediate grounds for rejection. They don't want their shiny new drug to look bad because one of the handful of people in the early trials had an allergic reaction to it. There's a general tendency towards immune hypersensitivity, so any known allergy is a risk factor for other allergies - people with hayfever are disproportionately likely to have asthma or eczema.
If you're applying for a clinical trial because you need the money, you might want to be economical with the truth. They'll check your medical records for anything you've told your GP about, but if you haven't told your GP about it then they're none the wiser. If you have told your GP about something in the past, then you tell them that it cleared up quickly and hasn't caused you any bother since.