The first two wave types, P and S , are called body waves because they travel or propagate through the body of Earth. The latter two are called surface waves they the travel along Earth's surface and their amplitude decreases with depth into Earth.
The causes are many and can have bacterial infection, seborrheic dermatitis of the face or even a scalp, rosacea, allergies, and in very rare cases, the lice. If the itchy eyelids is brought about by seborrheic dermatitis then you may develop dry, flakey patches of skin on the eyelid.
Rubbing your eyelids can make the skin on your eyelids look red and, over time, can cause then to thicken. Eyelid inflammation (blepharitis) Blepharitis, an inflammation of the eyelids, causes redness, irritation; and itchy, crusty eyelids. Insect bites. Redness, swelling, pain, itching, bumps are common symptoms of insect bites. Insect sting. An insect sting may be followed by redness, swelling, and itching. Dermatomyositis