Hi By the symptoms you mentioned, its more a kind of allergic reaction. Please check whether they had any exposure to any allergens. Were there any incidence like this before? Does there any history of asthma,eczema,hay fever etc? Please stay away from allergens as they may cause severe allergic reactions. The symptoms mentioned also shows a possibilty of Scarlet fever which is a streptococcal bacterial infection characterised by red, itchy rash on the neck and face than can move down the body,red and swollen tongue, sore throat,fever etc. It needs an immediate treatment to avoid complications. However a right diagnosis about this case can be ruled out by clinical examination. I suggest you to consult a Dermatologist as early as possible and get the right diagnosis and treatment. Hope this information help Thank you