How dangerous is fever for my child, can it causes brain damage?

Parents often worry a lot and losses sleep, when their children have fever in spite of fever being helpful and harmless. Sometimes the child does not have really fever but feels warm when touched, which could have many other reasons like the temperature of parent’s hands when touching the kid or when child is playing hard or crying or getting out of a warm bed or in a hot weather because in these cases the child is giving off heat. In fact measuring the child’s simply by touching skin is shown to be misleading in at least 40% of cases.
Parental concerns usually rises because of the belief that fever is a disease rather than a symptom of illness. This misconceptions and unrealistic concerns about the fever which ranges from thinking about the brain damage, losing their children and the disease causing the fever is potentially dangerous rather than relatively benign is termed fever phobia, and I hope the following details can help the parents to be more realistic when their children is febrile:
1) Temperature should be measured by thermometer, and the most accurate is the mercurial thermometer, putting under axilla, in mouth or rectal depending on the age of the child. Axillary temperature above 37.5 deg Celsius, rectal temperature more than 38 deg Celsius and oral or mouth temperature more than 37.7 degree Celsius is considered as fever.
2) Fever is a friend and is a body’s way of fighting infection by activating immune system of child.
3) Fever rarely goes above 40.5 – 41 degree Celsius and by itself doesn’t cause brain damage; only temperature above 42.2 degree Celsius can cause brain damage. It also does not increase the risk of speech delay or learning problem.
4) Fever only needs to be treated if they cause discomfort and this usually doesn’t happen unless it gets above 38.8 degree Celsius. Usually the brain has a thermostat and help for the fever not to go about 40 degrees Celsius.
5) The level of fever doesn’t indicate the type or severity of the disease causing the fever but other symptoms such as extreme fatigue or loss of appetite , how the child looks, does he play when his temperature is down ,is he playful or looks sick are important but the level of temperature is not , exception is when the child is less than 6 months old and fever specially high temperature can be the indication of a serious problem in some of them.
6) Some parents are worried about fever causing convulsion or seizure. Only 4 % of children can have seizure with fever and these are mostly special cases with a family history of seizure, child with hypoxic insult in the past or one who had once febrile seizure before. Most febrile seizure is really harmless, it may look scary to watch but it stops within 5 minutes and don’t cause any permanent harm.
QUESTION No. 2: When do I need to get worried about my febrile child and to seek immediate contact with my doctor?
1- Fever of any degree especially high fever in infant less than 6 month of age.
2- If the fever persist for more than 3-4 days and the cause of the fever is not clear
3- When your febrile child looks really sick, does not like to play, has poor appetite and is getting listless and weak.
4- If your child had already once febrile convulsion in the past.
5- If your child cries constantly and is very sensitive to touch especially in infants less than 1 year of age.
6- If you’re febrile child is also having difficulty in swallowing , have respiratory distress ,or is having diarrhea.