Cold sensitivity or cold intolerance is unusual discomfort felt by some people when in a cool environment.There is much variation in the sensitivity to cold experienced by different people, with some putting on many layers of clothing while others in the same environment feel comfortable in one layer.Cold sensitivity may be a symptom of hypothyroidism, anemia, fibromyalgia or vasoconstriction. Vitamin B12 deficiency usually accompanies cold intolerance as well. There are other conditions that may cause a cold intolerance, including low body weight, high body temperature and low blood pressure. There may also be differences in people in the expression of uncoupling proteins, thus affecting their amount of thermogenesis. Psychology may also play a factor in perceived temperature. See also
Apparent temperature
Thermoception
Raynaud syndrome


== References ==
Klippel–Feil syndrome (KFS), also known as cervical vertebral fusion syndrome, is a rare congenital condition characterized by the abnormal fusion of any two of the seven bones in the neck (cervical vertebrae). : 578  It results in a limited ability to move the neck and shortness of the neck, resulting in the appearance of a low hairline.The syndrome is difficult to diagnose, as it occurs in a group of patients affected with many different abnormalities who can only be unified by the presence of fused or segmental cervical vertebrae. KFS is not always genetic and not always known about on the date of birth. The disease was initially reported in 1884 by Maurice Klippel and André Feil from France. In 1919, in his Doctor of Philosophy thesis, André Feil suggested another classification of the syndrome, encompassing not only deformation of the cervical spine, but also deformation of the lumbar and thoracic spine. Signs and symptoms
KFS is associated with many other abnormalities of the body, hence thorough evaluation of all patients with fused cervical vertebrae at birth is required. Furthermore, it is unclear whether KFS is a unique disease, or if it is one part of a spectrum of congenital spinal deformities.KFS is usually diagnosed after birth.