In adults, eczema occurs most frequently on the hands and elbows, and in bending areas such as the inside of the elbows and back of the knees. In young children, eczema is often seen on the elbows, knees, face, neck, and scalp. Signs and symptoms of atopic eczema include: 1  Itchiness. 2  Skin redness.
Sphingolipids are composed of a backbone of sphingosine which is derived itself from glycerol. Sphingosine is N-acetylated by a variety of fatty acids generating a family of molecules referred to as ceramides. Sphingolipids predominate in the myelin sheath of nerve fibers.
Phospholipids consist of a polar molecule, a phosphate group, a glycerol unit and two fatty acids. They are found in cell membranes, which enclose the cytoplasm and other parts of a cell. Steroids include cholesterol, cortisone and sex hormones, such as estrogen, testosterone and progesterone. They have a carbon backbone that contains four fused ring-like structures.