Indusium: the case made by an insect larva: a membranous layer of the embryo of Locustidae below the serosa. Explanation of Terms Used in Entomology John. B. Smith. serosa: the outer membrane that envelops the forming embryo, the amnion and the remainder of the egg. Explanation of Terms Used in Entomology John.
In essence, your body forms an allergic reaction to stress. Unfortunately, stress can not be eliminated with histamine, so instead, the histamine just causes hives to appear on your face, neck, chest and other parts of your body.
The same person may also have different symptoms over time. Allergic reactions may occur suddenly, or develop after months of exposure. Contact dermatitis often occurs on the hands. Hair products, cosmetics, and perfumes can lead to skin reactions on the face, head, and neck. Jewelry can also cause skin problems in the area under it.