Itching

It is still not clarified in full detail how itching develops. It was long assumed that itching is caused by a subtle stimulation of pain nerves and is also transmitted via these. That is why itching is also referred to as the 'younger brother of pain'. However, more recent research results show that there are special nerve pathways in the skin for itching. We are far from knowing all of the carrier substances and their interaction.

Itching is usually countered with scratching or rubbing. This, however, stimulates inflammatory reactions of the skin, during which histamine and other mediators of inflammation are distributed. These also result in stimulation of the mediating nerve endings - existing itching is further intensified. Scratching can also result in minor injuries to the skin. Foreign substances can penetrate into the skin; the immune system reacts with inflammation. Infection can also result from bacteria penetrating the skin.

Each of these processes causes itching so that the 'cycle' of itching - scratching - inflammation processes - itching is
difficult to break. Itching, or maintained
however, can be caused, not only on
directly in the skin, e.g. through skin
diseases or by scratching,
but also due to damage to
the nerves that transmit the
itching (e.g. with herpes
zoster), through neurological or
psychogenic illnesses (e.g. with
depression, fear, stress, etc.)
and through illnesses of central
structures (e.g. with brain tumours).