Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Seek urgent or emergency care for difficulty breathing, blue or gray lips, severe dehydration, confusion, a seizure, a stiff neck with severe illness, fainting, or rapidly worsening symptoms.
An emergency medical identification card or phone record can help inform clinicians about the immune disorder and current treatment.
Contact the medical team promptly for fever, worsening cough, ear pain, persistent diarrhea, an infected wound, or other signs of infection.
Early assessment is especially important if symptoms are not improving as expected.
Routine follow-up with an immunologist is needed even when infections are well controlled.
Visits may review infusion tolerance, IgG levels, antibiotic use, missed school or work, growth in children, and any new breathing, hearing, joint, or digestive symptoms.
A persistent wet cough, falling exercise tolerance, or repeated pneumonia should be reported rather than saved for the next routine visit.
The article also says
People with a history of lung infections may need periodic lung function testing or imaging.
Every sign above is quoted from the sofidex article on Agammaglobulinemia. If you are not sure, err upward — it is always reasonable to be checked.