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.
Itchy eyelids can result from any condition that irritates, inflames or infects the eyelid. Allergies, infections, and even lack of sleep can cause your eyelids to itch.Itchy eyelids are commonly associated with other symptoms like redness, swelling, a gritty feeling in the eye, irritation, lumps or bumps, increased tear production, or discharge. Allergies are the most common cause of itchy eyelids.An allergy that affects your eyelid may be local, such as an allergic reaction to eye makeup, or more generalized, such as hay fever.tchy eyelids are commonly associated with other symptoms like redness, swelling, a gritty feeling in the eye, irritation, lumps or bumps, increased tear production, or discharge. Allergies are the most common cause of itchy eyelids.