What causes pruritus?
Itchy skin is an extremely common phenomenon, affecting between 13% and 30% of the population(1). Skin itching affects everyone: babies, children, adults, the elderly, men, women, pregnant or breastfeeding mothers. Pruritus can be concentrated on one or more parts of the body, or it can be generalized pruritus.
Pruritus is a common yet complex sensation. Many people think that it is a simple release of histamine when in fact pruritus involves many structures, nerve fibers and biological molecules like cytokines or neurotransmitters. There is not one single type of pruritus, there are many.
" Why do we scratch?" is often a difficult question to answer. The causes of pruritus and itching are extremely variable from one individual to another.
Itching sensations on the skin of dermatological origin are the best known and easiest to understand because they are accompanied by skin lesions such as plaques or spots. It is precisely these skin lesions that cause this type of pruritus. Among the main pruritic dermatoses, we can list eczema, psoriasis, seborrheic dermatitis and even scabies, chicken pox, insect and plant bites, sunburns, etc. Itching all over the body can also result from non-dermatological causes, and this is where everything gets more complicated. In this case, pruritus is not associated with one or more skin lesions that could explain it. This is pruritus sine materia, in other words pruritus without spots or plaques. The sources of pruritus sine materia are varied: kidney or liver diseases, endocrine disorders, cancers, medications, pregnancy, neurological diseases, psychiatric diseases, etc.
Advanced age is also a cause of pruritus in its own right. Many elderly people are affected by senile pruritus, at home or in an institution. Their distress in the face of itching should not be overlooked: family, friends and medical staff must be attentive to the elderly and their needs.
Cancer treatments are another possible cause of pruritus. The itching related to cancer treatments can be intense. It can affect the skin as well as the scalp, and accompany any type of treatment: chemotherapy, radiation therapy, targeted therapy or immunotherapy.
Finally, many environmental parameters can accentuate pruritus: hard water, climatic conditions, perspiration, friction, the use of unsuitable cosmetics, stress, etc.