Teething is the process by which an infant's first teeth (the deciduous teeth, often called 'baby teeth' or 'milk teeth') sequentially appear by emerging through the gums, typically arriving in pairs. The mandibular central incisors are the first primary teeth to erupt, usually between 6 and 10 months of age. It can take several years for all 20 teeth to complete the tooth eruption. Though the process of teething is sometimes referred to as 'cutting teeth', when teeth emerge through the gums they do not cut through the flesh. Instead, hormones are released within the body that cause some cells in the gums to die and separate, allowing the teeth to come through. Teething is the process by which an infant's first teeth (the deciduous teeth, often called 'baby teeth' or 'milk teeth') sequentially appear by emerging through the gums, typically arriving in pairs. The mandibular central incisors are the first primary teeth to erupt, usually between 6 and 10 months of age. It can take several years for all 20 teeth to complete the tooth eruption. Though the process of teething is sometimes referred to as 'cutting teeth', when teeth emerge through the gums they do not cut through the flesh. Instead, hormones are released within the body that cause some cells in the gums to die and separate, allowing the teeth to come through. Teething may cause a slightly elevated temperature, but not rising into the fever range of greater than 38.0 °C (100 °F). Higher temperatures during teething are due to some form of infection, such as a herpes virus, initial infection of which is extremely widespread among children of teething age. The level of pain that a baby can handle will be different for each child. Some may appear to suffer more than others while they are teething. The soreness and swelling of the gums before a tooth comes through is the cause for the pain and fussiness a baby experiences during this change. These symptoms usually begin about three to five days before the tooth shows, and they disappear as soon as the tooth breaks the skin. Some babies are not even bothered by teething. Common symptoms include drooling or dribbling, increased chewing, mood changes, irritability or crankiness, and swollen gums. Crying, sleeplessness, restless sleep at night, and mild fever are also associated with teething. Teething can begin as early as 3 months and continue until a child's third birthday. In rare cases, an area can be filled with fluid and appears over where a tooth is erupting and cause the gums to be even more sensitive. Pain is often associated more with large molars since they cannot penetrate through the gums as easily as the other teeth. Some noticeable symptoms that a baby has entered the teething stage include chewing on their fingers or toys to help relieve pressure on their gums. Babies might also refuse to eat or drink due to the pain. Symptoms will generally fade on their own, but a doctor should be notified if they worsen or are persistent. Teething may cause signs and symptoms in the mouth and gums, but does not cause problems elsewhere in the body. Pulling on the ears is another sign of pain; the pain in the mouth throbs throughout the baby's head so they pull their ears believing that it will provide relief. Mild rash can develop around the mouth due to skin irritation that is caused by excessive drooling or dribbling.