Itching

Pruritus (itch) can be described as “an unpleasant sensation in the skin which leads to the desire of scratching” (1).

• can be widespread or localized
• also seen in the squamous epithelium of the conjunctivae, mouth, nose, pharynx and anogenital area and in the ciliated epithelium of the trachea (1)

It is frequently a distressing symptom which may interfere with the quality of life of a patient, for example preventing normal sleep and should therefore be taken seriously.

Itching which is experienced as a feeling, arises in the skin from a cutaneous nerve stimulation mediated via several substances (histamine, vasoactive peptides, enkephalins, substance P and prostaglandins) (3).

The sensation of Pruritus may be enhanced by chronic or intense scratching creating a distinctive itch-scratch-itch cycle (4).

The incidence of pruritus increases with age (1) and is one of the most common complaints in the elderly patient population. Most often dry skin, otherwise known as xerosis is the commonest cause in these patients (3).

Reference:

• (1) Twycross R et al. Itch: scratching more than the surface. Q J Med 2003; 96: 7-26
• (2) Moses S. Pruritus. AAFP 2003; 68(6)
• (3) National cancer institute 2008. Pruritus
• (4) Steinhoff M et al. Neurophysiological, Neuroimmunological, and Neuroendocrine Basis of Pruritus. JID 2006; 126:1705-1718.