The Red line seen is a wheal
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Greetings of the day
The Red line which you see is a wheal. It occurs due to increased capillary permeability as a form of type 1 hypersensitivity
reaction. It can occur even after slight trauma which is insignificant. There is no cause of concern as it is self limiting. If it still persist taking antihistamine like Pheniramine
maleate in consultation with your physician will help.
Wishing you a healthy life.
In case you require any further clarification kindly get back to me.
Dr Deepak Kishore