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.
Eyelid Rash Causes. A number of factors may act as the cause of rash on eyelids. Some of the possible causes for this disorder are : Eyelid Rashes can often arise as a side effect of medicines. Certain drugs are known to give rise to rashes in different parts of skin of the body, including the eyelids.