Pruritus: definition, causes and treatments

What is pruritus?

In medical terms, pruritus (from the Latin pruritus) includes all itchy skin regardless of its place on the patient’s body. This symptom, without pain, but leading to scratching of the skin and therefore to possible skin lesions, can have many causes, ranging from viral infection (herpes), to skin irritation, eczema , to the simple bite of a mosquito. However, these disorders can be grouped into two categories: pruritus related to a skin lesion or disease.

In case of pruritus, the more or less acute symptoms begin with the same picture in patients: “It is initially an unpleasant feeling of itching, associated or not with a feeling of tightness. The itching can be local or generalized (that is to say occurring all over the body), sometimes in the form of plates”explains Dr. Marie Jourdan, dermatologist at the Center Laser International de la Peau-Paris (CLIPP).

The sensation of the need to scratch arises from nerve endings present on the surface of the skin, by stimulation of small specific receptors. Transmitted by nerve impulses, it sends information about the itching sensation to the brain, via certain neurotransmitters: histamine, serotonin and prostaglandin. These activate the sensory, emotional and motor areas of the brain, creating the need to scratch in the patient. “Hence the vicious “itch-scratch” cycle, which can cause scratching skin lesions, making pruritus and itching worse”, adds the dermatologist.

What are the causes of pruritus?

The causes of pruritus can be extremely diverse, and of varying severity. A skin and medical examination may be necessary to determine the origin of the pruritus in the patient.

This pruritus can be associated with different situations, for example linked to a local problem on the skin:

• An infection : viral (herpes, shingles, chickenpox, etc.), mycotic or bacterial (impetigo) which create a skin reaction;
• Skin tenderness or inflammation : eczema, psoriasis, urticaria, lichen planus, dry skin, atopic dermatitis…;
• Environmental irritation : allergies to certain materials and products (cosmetic substances, metals, textiles, food or medicines), irritations due to heat or humidity which can cause dryness or mycosis;
• A reaction to insects, parasites or plants : mosquitoes, fleas, bees, wasps, lice, or even nettles.

In other cases, pruritus will be a symptom of a health problem, and will help to put on the trail of internal diseases: liver disease (hepatic cholestasis), kidney failure, diabetes, blood cancer, gland disease thyroid can also induce skin dryness, lesions or itching.

“Finally, it can be a neurological disease: in this case the skin receptors will be stimulated by stress, linked to this neurological disease. We can evoke depression, anxiety, obsessive compulsive disorders (OCD)”adds Dr. M. Jourdan.

What are the factors that promote pruritus?

• The stress. Whatever the cause, stress will promote the stimulation of skin receptors, and lead to more scratching, and thus more serious skin lesions. In case of stress noted as aggravating the condition of the skin, the doctor can also prescribe low-dose antidepressants;
• The dryness of the skin is also a factor favoring pruritus and its aggravation.

“You have to be aware of what favors the stimulation of the receptors, and act accordingly”explains Dr. Marie Jourdan.

In case of problematic itching, the dermatologist also offers solutions to learn how to quickly reduce the stimulation of these receptors:

• Prefer loose cotton clothes, to very tight ones, synthetic, for example;
• Limit yourself to one shower a day, carefully moisturizing the skin afterwards;
• Rinse the skin with cold water, especially the itchy area in the event of an attack of scratching;
• Perform skin massages, with suitable vegetable oil or moisturizing cream, a substance tolerated by the skin.

“The objective is to divert attention from scratching, allow time for the pH of the skin to regulate itself, and the itching sensation gradually fade”says the dermatologist.

Pruritus: what treatment should be adopted?

Pruritus being a symptom, after a health examination, the doctor will first consider a treatment targeting the cause of the symptom, then reduce the aggravating factors as much as possible until the itching decreases. The drugs prescribed will depend on the origin of the pruritus.

“For example, for pruritus due to an allergy, we treat by administering an antihistamine; for a virus, an antiviral; if the pruritus is linked to a parasite, an antiparasitic; an antifungal cream against mycosis, etc.”, explains Dr. Marie Jourdan. When the cause of the dermatitis is treated, the inflammation will subside, and the scratching will then gradually disappear.

Finally, in the case of pruritus and skin that feels tight and itchy, occasionally or chronically, it is possible to add emollient treatments against the main cause to the treatment envisaged, in order to moisturize the skin.

As said above, and as far as possible, the treatment of skin disorders can also lead to limiting stress, which is one of the main aggravating factors of pruritus. Relaxation, yoga, massages are options to divert attention from cutaneous sensations and to relax durably. In short, learning to take care of yourself in several different ways is as good for your morale as it is for your skin.