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.
Rare but dangerous causes of eyelid swelling are infection within the orbit and around and behind the eye (orbital cellulitis) and blockage of a vein at the base of the brain by an infected blood clot (cavernous sinus thrombosis).