There is a good guide on the NHS website which describes various conditions affecting children. There is advice on how to diagnose them, how to treat them and if further advice should be consulted.
NHS childhood illness slideshow
When Should I Worry?
Having an ill child can be a very scary experience for parents. If you understand more about the illness it can help you to feel more in control. This booklet is for parents (and older children) and deals with common infections in children who are normally healthy.
Download the booklet
Most symptoms of a fever in young children can be managed at home with infant paracetamol. If the fever is very high, they may have an infection that needs treating with antibiotics.
Head lice are insects that live on the scalp and neck. They may make your head feel itchy. Although head lice may be embarrassing and sometimes uncomfortable, they don't usually cause illness. However, they won't clear up on their own and you need to treat them promptly
Nosebleeds (also known as epistaxis) are fairly common, especially in children, and can generally be easily treated.
These links all come from trusted resources but if you are unsure about these or any other medical matters please contact your doctor or pharmacist for advice