Eczema is a chronic inflammatory skin condition. In most cases it develops in early childhood. It is typified by dry itchy skin and is episodic in nature (except in severe cases). Most children with eczema will experience flares, sometimes as often as 3-4 times per month. (NICE Guidelines 2007).
And Dilshad Marikar explains how to assess eczema here.
The principles of eczema management are summarised here
And if you want to hear more, then nobody does it better than Jean Robinson at DFTB19:
Nummular eczema (also known as discoid eczema) is a chronic skin condition. It causes skin to become erythematous, prutitic and cracked as with other forms of eczema. It is differentiated by its distinctive circular or oval patch formation. It can affect any part of the body though usually does not affect the face or scalp. There may be only one discoid patch or several. Discoid eczema often starts as a small group of bumps. On darker skin these patches can be dark brown or paler than the skin around them. Patches that return after clearing tend to appear in the same place as the first outbreak. As with eczema a combination of emollient use, topical corticosteroids varying in strength depending on the severity of the flare and location of the patches and antihistamines to reduce pruritic symptoms.