Hello,
The symptoms looks similar to Raynaud's phenomenon.
Because you have the symptoms immediately after the cold water spills.
Please check whether you have any of the following additional symptoms.
1. Pin and needles sensation in hands
2. Turning of hand to white then to blue
3. Returning of pink color on exposure to hot.
It may associated with plenty of collagen and
auto immune disorders.
It may itself as an idiopathic.
Please do the following investigations.
1. Digital artery pressure
2. Doppler ultrasound
3. Full blood count
4.
Blood test for urea and electrolytes
5. Thyroid function tests: this may reveal
hypothyroidism.
6. An
autoantibody screen
7. tests for rheumatoid factor
8.
Erythrocyte sedimentation rate, and C-reactive protein
Then write back for further queries.
Wishing you good health.