The rules nobody reads until they have started

Yes, but not straight after a dose. Typical OIT protocols ask for at least two hours without exercise after dosing, and some ask for three, along with avoiding hot showers or baths in that window — exercise and heat both lower the threshold at which a reaction can occur. Protocols also commonly say that if strenuous exercise happened shortly before a scheduled dose, the dose should wait until flushing, sweating and a raised heart rate have settled. For a child with training most evenings, this is the constraint that shapes the whole family schedule.

On oral immunotherapy, a short gap is usually tolerated and a longer one is not. Many protocols allow up to three consecutive missed doses and let you resume at the same dose on the fourth day; beyond that, you call the clinic, and the next dose may need to be given in the office rather than at home. The reason is real rather than bureaucratic: tolerance to the protein can fade, and resuming a full dose after a longer gap carries genuine risk. Sublingual protocols are more forgiving of gaps, but you should still tell whoever supervises you.

On oral immunotherapy, dosing is typically held during fever, vomiting, or an acute illness, because being unwell raises the chance of a reaction. That means an ordinary childhood winter can interrupt treatment several times, and each interruption may need a conversation about how to restart. This is one of the less visible reasons multi-year courses get abandoned.

The dose itself is much smaller — food sublingual immunotherapy generally uses no more than about 4 mg of allergen protein per day, held under the tongue for one to two minutes, against the gram-scale doses swallowed on oral immunotherapy. Only the first dose typically needs to happen in a clinical setting, and a pre- or post-dose rest period is generally not required. That is the source of both its advantages and its limitation: less allergen, fewer reactions, and a smaller rise in the reaction threshold.

No, and we are not going to argue that it is. In a direct comparison in peanut-allergic children, oral immunotherapy raised the reaction threshold roughly 141-fold at 12 months against roughly 22-fold for sublingual. If you can sustain oral immunotherapy and have a centre within reach, the evidence on threshold favours it. The case for sublingual is that the trade of a smaller effect for a schedule a family can actually keep is a real trade — not a consolation prize.

There is published work on exactly that. A study in the Journal of Allergy and Clinical Immunology: In Practice examined bypassing the oral immunotherapy build-up phase with an initial period of sublingual immunotherapy for higher-risk food allergy — the build-up being the phase that carries the most reaction risk. That positions the two as sequential rather than rival. It is a conversation to have with an allergist who runs both, not something to arrange yourself.