Juvenile dermatomyositis

It is the largest organ of the human body and the main protective barrier against the external environment. It is composed of cells that are organized in different layers:

• Epidermis or outer layer. It is made up of cells in continuous renewal. It has no blood vessels, it is nourished by diffusion from the intermediate layer.
• Dermis or intermediate layer. Represents the second barrier against trauma. It contains hair follicles, sebaceous glands, blood vessels and sensitive endings. It has the function of nourishing and supporting the outer layer, thermoregulating and sensitive.
• Hypodermis, deep layer or subcutaneous tissue. It is mainly used to accumulate fat. It has abundant blood vessels and nerve endings.

In JDM there is a characteristic inflammation of the skin, giving rise to different types of lesions that we will see below.