Fewer than 5% of infants who cry excessively turn out to have an underlying organic disease, such as constipation, gastroesophageal reflux disease, lactose intolerance, anal fissures, subdural hematomas, or infantile migraine. Babies fed cows milk have been shown to develop antibody responses to the bovine protein, causing colic. Studies performed showed conflicting evidence about the role of cows milk allergy. While previously believed to be related to gas pains, this does not appear to be the case. Another theory holds that colic is related to hyperperistalsis of the digestive tube (increased level of activity of contraction and relaxation). The evidence that the use of anticholinergic agents improve colic symptoms supports this hypothesis.Psychological and social factors have been proposed as a cause, but there is no evidence. Studies performed do not support the theory that maternal (or paternal) personality or anxiety causes colic, nor that it is a consequence of a difficult temperament of the baby, but families with colicky children may eventually develop anxiety, fatigue and problems with family functioning as a result. There is some evidence that cigarette smoke may increase the risk. It seems unrelated to breast or bottle feeding with rates similar in both groups. Reflux does not appear to be related to colic. Diagnosis
Colic is diagnosed after other potential causes of crying are excluded. This can typically be done via a history and physical exam, and in most cases tests such as X-rays or blood tests are not needed.
The term Micronychia may refer to

Micronychia (plant), a genus of plants in the family Anacardiaceae
Micronychia (fly), a genus of flies in the family Tachinidae
abnormally small finger- and toenails