What is Pruritus?
Pruritus is an unpleasant sensation that provokes a reflex or desire to scratch to relieve the undesirable sensation. It is commonly referred to as “itch” and is experienced by the general population.
Pruritus is experienced by anyone regardless of gender and age affecting both children and adults and even newborn infants. The irritating sensation can be localized or it can be generalized, depending also on the cause of the itchiness. Pruritus can result to an unpleasant sensation or irritation to the skin although it is generally not a serious condition nor associated with any mortality.
Pruritus originates in either of the two mechanisms known as the “peripheral mechanism and central mechanism”.
Peripheral mechanism begins in the skin and is stimulated by physical stimuli and neural pathways. Mechanical stimuli such as pressure, gentle touch and texture of cloth and other surfaces can instigate this undesirable sensation. Thermal and electrical stimuli are also included in the peripheral mechanism. Chemical mediators such as histamine and other chemical substances are also considered to trigger pruritus.
Central mechanism originates from the central nervous system which may or may not result from damages in the nervous system.
In psychiatric problems, pruritus is also being associated and is often considered as among the symptoms.
Pruritus is the medical term for itch and is defined as an irritating and undesirable sensation that provokes an individual to scratch in order to relieve the itch. The symptom is the itchiness itself while various symptoms can be associated depending on the underlying condition, diseases or disorders.
Common symptoms that may be associated with pruritus include the following:
- Formation of blisters
- Burning sensation
- Swelling and inflammation
- Drying and scaling of the skin
- Crusting and cracking of the skin
- Pain may also be experienced
- Secretions from the lesions, pustules and sores
Pruritus may also occur with other conditions that affect the whole body system and such symptoms may include the following:
- Nausea which may or may not have vomiting
- Development of hives or rash
- Sneezing and runny nose
- Swelling and inflammation
- Dry mouth
- Cramping and abdominal pain
Although generally not a serious or life-threatening condition, pruritus may be an associated symptom of a serious or life-threatening condition and the symptoms may include the following:
- Rapid swelling of the face and tongue
- Tachycardia or the rapid heart rate
- Difficulty in breathing or shortness of breath
- Loss of consciousness
- Confusion or lethargy
The cause of pruritus is varied and numerous and is classified accordingly.
Localized pruritus is pruritus that is confined to a limited area only. Localized pruritus is often neuropathic and occurs in association with a primary rash such as dermatitis. The neuropathic onset is often the result of a compression of the nerves of the skin or a degeneration extending towards the spine or from the spine. Although limited to a particular part of the body only, incessant scratching of pruritus may result in the development of prurigo and lichen simplex. Other causes of localized pruritus may include the following:
- Head lice
- Seborrheic dermatitis
- Lichen sclerosus
- Tinea pedis
- Vulvovaginal candida
- Trigeminal trophic syndrome
- Pruritus vulvae
- Pruritus ani
Systemic pruritus is the result of systemic disease often occurring as part of the manifestation of the primary disease itself. The causes of pruritus may include the following:
- Chronic renal failure
- Iron deficiency anemia
- Lymphatic leukemia
Skin diseases are also implicated in the cause of pruritus and are part of the symptoms of the disease process. Skin diseases that can cause pruritus include the following:
- Atopic dermatitis
- Dry skin
- Allergic contact dermatitis
Hormonal pruritus is found in pregnant women and prior to the onset of menstrual period. Pruritus is also part of the symptoms of menopause.
Exposure to external factors commonly triggers the onset of pruritus. Insect bites and infestation can result to pruritus often as an allergic reaction to certain chemicals emitted by the insect that bites. Reaction to certain medication is also considered in the exposure to external factors that can cause the pruritus. Pruritus resulting from medication is often the adverse reaction of an individual from a certain medicine that usually occurs immediately after the medicine is taken in. Medicines such as opioids and aspirin can cause pruritus to some people. Allergens and other irritants also trigger pruritus. Irritants such as from the plants poison ivy and oak are known to cause pruritus immediately after contact with these plants. In allergens, people often experience pruritus upon exposure or contact with perfumes, detergent soaps, and certain cloth such as wool including also exposure to dyes and chemicals.
Pruritus is generally not life-threatening and permanent condition that can debilitate a person. Treatment is often not necessary although incessant scratching is not advisable as this can lead to further problems or complication.
The treatment of pruritus initially starts with the identification of the cause or the underlying condition that triggered the onset of the undesirable sensation. Relief of itchiness is the aim of treatment of localized pruritus. Systemic pruritus is prescribed with relief of symptoms while the main condition or the underlying condition is primarily treated.
Treatment often includes application of emollients, calamine lotion, and menthol or camphor lotion and topical corticosteroid in mild dosage. Oral medication may also be given such as antihistamine, thalidomide, opioid antagonist and doxepin.
Pruritus in Pregnancy
Pruritus is considered a leading dermatological symptom during the process of pregnancy. It is a normal occurrence among pregnant women even without the presence of any dermatological cause or condition. Itchiness is usually felt around the growing belly and breast which are often related to the stretching of the skin to accommodate the growing fetus and the activity of the mammary gland in producing milk.
Hormonal changes are also considered to be the cause of pruritus in pregnancy. The increase in the levels of estrogen often leads to itchiness and redness of the palm of the hands and sole of the feet of pregnant women. Pruritus however, resolves after the expulsion of pregnancy or delivery. Pruritus is also believed to be the result of bile pooling in the gallbladder and liver.