Understanding itch in epidermolysis bullosa (EB)

Epidermolysis bullosa (EB) is a group of genetic disorders in which the skin is extremely fragile. People with severe types suffer from widespread blisters and sores, sometimes also involving internal membranes. As well as pain, patients experience severe itch, particularly in healing wounds and surrounding skin. Scratching causes more itchy wounds leading to a vicious cycle of itching and scratching. This paper from international EB experts reviews what we know about EB itch. Itch occurs in all patients with severe recessive and junctional EB and in many patients with other types of EB. It can be made worse by healing wounds, dry skin and stress and is influenced by externally controlled factors such as temperature, humidity, dressings and morphine‐related drugs. Exactly why and how it occurs is complicated and not entirely understood, but current thinking is as follows. Damaged skin cells release chemicals which attract immune cells to the wound site. These cells in turn release ‘itch mediators’ which stimulate specific nerves in the skin. Those nerves transmit messages via the spinal cord to the brain where they are perceived as itch. At the same time the nerve endings in the skin release chemicals which attract more immune cells to the area in a feedback loop known as ‘neurogenic itch’. Similar mechanisms are probably responsible for itch following burns. Many different agents are used to treat EB itch but none is very effective. Newer targeted biological medicines seem promising. Increased knowledge about causes of EB itch will hopefully lead to better treatments. Linked Article:   Papanikolaou et al. Br J Dermatol 2021; 184 :816–825.