Hello and welcome to HCM,
Sudden
flushing of face, head, neck, arms, chest and legs is most probably due to
allergic reaction.
Allergic reaction can be due to some food item (nuts, sea food, milk etc.), environmental allergen (pollen, dust, mite etc.), drug or cosmetic>
Is there any history of exposure to any of these agents?
Relief from these symptoms after taking an anti-histaminic drug (
Benadryl) suggest that the symptoms were due to an allergic reaction.
Identification of the allergen and avoiding it in future is required.
You may consult your primary healthcare provider with detailed history to identify the allergen.
Thanks and take care
Dr Shailja Puri