"had onset" is correct and usable in written English.
You can use it when you want to describe the beginning of something, for example: "Her symptoms had onset about a week ago."
A pilot study of adults who had onset of juvenile dermatomyositis (JDM) in childhood, before current therapeutic approaches, to characterize JDM symptoms and subclinical cardiovascular disease.
The woman had onset of symptoms April 4.
None had onset pain localizing in the vertex region. 5.
In no subjects had onset pain been side locked.
In the elderly, two patients had onset of migraine without aura, whereas one patient had onset of migraine with aura at ≥55 years old.
More than half had onset pain bilaterally/centrally and in the cervico-occipital regions.
In Mack series of NDPH, 43% patients had onset of their symptoms during an infection [3].
Early/slow events shown in panels (a) and (b) had onset durations of about 1.8 2.0 s both in the amplitude and phase.
Verhagen et al. [16] described a patient from The Netherlands, who had onset in middle age of features of OM with abducens palsy.
Fifteen patients had onset of tension-type headache, two had trigeminal neuralgia and ten had unspecified headache at 55 years old and above.
Overall, 46%% of the elderly patients had onset of headache at ≥55 years old and headache starting at that age represented 19%% of headache in all ages.
