She needs to have her liver enzymes tested and specifically, bile acids. The only time I have ever heard of intense allover body itching is in liver conditions like Hepatitis and cholestasis.
How are her stools? Are they kind of light colored, do they float and/or is her urine dark?
I had a very intense, allover body itching that was out of this world on the drive-you-mad scale. It came on during pregnancy and it was called Intrahepatic Cholestasis of Pregnancy. Because I have a genetic weakness toward eczema, my itching and scratching produced rash, but normally cholestasis doesn't have an accompanying rash. Anything that heats the body aggravates the itch. There is an over the counter cooling lotion that helped me to keep my sanity. It's called Sarna, and it's available at Rite-Aide and Osco.
Obviously your daughter isn't pregnancy, but there is a cholestasis that affects children too called Progressive Familial Intrahepatic Cholestasis. Here are the symptoms:
PFIC usually occurs soon after birth (within six months) and is a very rapidly progressing disease. Sometimes children may not develop the disease until later in childhood and even into adolescence. Children with PFIC may exihibit some or all of the following:
• jaundice (yellowing of skin and/or eyes) – usually present soon after birth.
• severe itching (pruritis) due to bile build up in skin
• poor weight gain and/or growth (failure to thrive)
• enlarged liver and/or enlarged spleen
• lack of energy
• loss of appetite with nausea and vomiting
• foul smelling stools or fatty stools from the inability to absorp fat in the diet
• pale, grey stools – from bile dysfunction
• dark urine – excessive bilirubin in the urine.
Bile is made within the liver and is essential for the digestion and absorption of fats. Bile is transported from the liver to the small intestine through bile ducts. Children who suffer from PFIC are unable to drain bile from the liver even though the bile duct appears to be open and functional. Bile will then build up in the liver causing damage to liver cells.
I would definitely have the doctors rule out the liver.