Seborrhoea is the excessive production of oil on the scalp causing the follicle to distend. This can result in the hair falling out as the follicle can not grip it. The causes are many; diet, hormones, puberty, stress, hereditary, nervous system, allergies, medication, and the use of incorrect hair products and hair care. Its appearance is lifeless, dull & lacks elasticity. People who have greasy hair will often suffer from a greasy T-zone (forehead and nose).
With treatment No. 2 (No. 3 for scale) this condition is easily rectifiable.