Resolved Psoriasis-Like Rash in Toddlerhood, Now Mild Tendon/Finger Issues — Anyone Seen This Pattern?

Hi everyone, I’m trying to understand whether my son’s old skin issues could possibly be related to his current tendon/finger problems, or whether these are likely separate things.
Between July 2023 and around October/November 2023 (he was around 2 years old then), he had 2–3 episodes of a widespread rash. It started as pink raised bumps/papules, spread over large parts of the trunk/body, and some lesions later merged into larger dry/scaly patches. During the fading stage, some areas looked “drop-like.” Interestingly, the trunk rash itself was not very itchy, although he did have an itchy/flaky scalp around the same time.
Those episodes resolved with steroid creams and eventually completely disappeared.
Later on, he developed a different kind of skin issue that looked much more like eczema — very itchy patches mainly on the arms/fingers/hands. After starting Dupixent, that eczema-type rash resolved really well and has stayed controlled.
Now the current issue is that he has had:
ankle tenosynovitis previously,

and now persistent swelling/fullness and functional limitation in one finger.

Recent ultrasound showed possible very subtle flexor tendon sheath/tenosynovial thickening but no Doppler hyperemia, no fluid, and otherwise normal tendons/joints. MRI is scheduled soon. Bloodwork in 2024 after the rash episodes was reassuring/normal.
I’m trying to understand:
Has anyone had a child with temporary guttate-psoriasis-like rashes that completely resolved and never returned?

Can old inflammatory skin episodes be unrelated to later tendon issues?

Has anyone had mild tendon sheath swelling/finger fullness turn out to be mechanical/hypermobility-related instead of autoimmune?

If MRI later showed no active inflammation, what explanation did doctors give for visible swelling/fullness?

Not looking for a diagnosis — just trying to understand how these kinds of stories sometimes evolve.