How can I tell if my 7mo old child has hand foot mouth disease; there have been 3 cases in his class?

Oral ulcers, skin ras. He may get ulcerative lesions in the mouth that are painful and small vesicular lesions one the fingers, plams, toes and soles of the feet. There is usally a 3-6 day incubation period from exposure till lesions appear.
Very infectious. Tender vesicles in mouth, tongue, back of hand, some have rash on feet. This is a viral condition.
Ulcers. Caused by a virus, ulcers in the mouth are a good clue. Occasionally blisters on the hands and feet, but not always. Other sx may include fever, diarrhea, sore throat, and congestion. A good physical exam by the pediatrician can make this diagnosis. Remember that antibiotics do not cure this infection.

Related Questions

Can you guys tell me how best to treat a hand foot & mouth disease infected my 14 yrs old daughter?

Supportive care. There are no medicines that will shorten the duration of this disease (caused by a virus). Make sure that she does not get dehydrated during this time. Pain relief with Ibuprofen can help. I hope she feels better soon.

How young can a child be, for getting coxsackie hand-foot-mouth disease?

Infants. Maternal antibodies likely protect newborns for the first 2-3 months if the mother had the hfm strains in her lifetime, but unprotected newborns may be susceptible to these human only strains. They may not rash out like older kids. I have seen hfm in kids as early as 6m.
Birth. If the mother of the infant is not immune to the varient that the infant is exposed to then the infant has no immunity and is at risk of the disease. Currently there is an unusual variant of the disease in the us and most people are at risk.

Are child care centers suppose to send out notices if children are sent home with hand, foot & mouth disease?

I don't know what. The official laws are, but I would definitely think so. It is contagious and I would think any contagious medical condition parents should be made aware of.

Is it possible for a child to be wrongly diagnosed with hand-foot-mouth disease?

Yes. There is a lot of variability of symptoms. One has to be careful in making the diagnosis as there are many conditions that simulate hand-foot-mouth disease.