Usually allergens are small molecules which can penetrate the layers
of the skin and sweating is known to enhance this
action. Stinging insects, Aeroallergens (uncommon), Foods and additives like Milk, egg, peanuts, nuts, soy, and wheat are the most common agents to cause such reactions.
Topical lotions such as calamine decreases pain and pruritus. Systemic antihistamines (antipruritics) such as hydroxyzine or cetirizine against prescription may be helpful.