Humanity has never been able to decide what to do with hair: whether to remove it, cultivate it or adorn it. A vast amount of energy and time goes into the individual's consideration of hair styles and hair colour, of maintenance or suppression of moustaches and beards, and of tolerance or removal of limb and torso hair growth. Another concern is with the healthy growth of scalp hair, which may be interfered with by trauma, inflammation or vascular insufficiency (in terms of follicle viability). General health affects hair growth; and nutritional deficiencies, metabolic changes and major internal diseases may be cited as inhibiting factors. Excessive radiation, anticoagulants and antimitotic agents cause hair loss as well. Genetic factors may produce abnormal hair, examples of which are: beaded (monilethrix): ringed (pili annulati); and twisted (pili torti). Hair and hair situated diseases include ringworm infections, acne, alopecia (baldness), head lice infections, and epidermal scurf such as dandruff. Cosmetic cover-ups which often take the place of adequate medical treatment may often lead to effects worse than the original malady.