Pruritus: Causes

What causes pruritus?

Pruritus is a common symptom of allergies, inflammation, or even physical irritation. Pruritus results from a tingling, irritating or uneasy sensation on the skin. It may occur in conditions affecting only a small area on the skin or along with more generalized conditions, such as hives or as a side effect of some medications.

In other cases, chronic conditions or cancers can be the cause of itching, or pruritus.

Skin causes of pruritus

Pruritus may be caused by skin disorders including:

• Atopic dermatitis (skin inflammation caused by an allergen)
• Contact dermatitis (localized skin irritation caused by contact with a particular substance)
• Dryness of the skin
• Eczema (skin inflammation or irritation)
• Parasite infestation, such as scabies, head lice, or pinworm
• Rash
• Sunburn

Other causes of pruritus

Pruritus can also have other causes including:

• Allergic response
• Breast cancer
• Drug allergy, such as penicillin or codeine
• Food allergies (allergic reaction to certain foods)
• Insect bite allergy such as a bee sting
• Lymphoma
• Medications, such as antibiotics (sulfonamides, penicillin), opiates (morphine and its derivatives), phenothiazines like chlorpromazine (Thorazine) and prochlorperazine (Compazine), or isoniazid
• Pregnancy
• Vitamin A supplementation

Serious or life-threatening causes of pruritus

In some cases, pruritus may be a symptom of a serious or life-threatening condition known as anaphylaxis (life-threatening allergic reaction) that should be immediately evaluated in an emergency setting.

Questions for diagnosing the cause of pruritus

To diagnose your condition, your doctor or licensed health care practitioner will ask you several questions related to your pruritus including:

• When did you first notice your itching?
• On what part of your body do you notice the itching?
• Do you have any other symptoms?
• What medications are you taking?

What are the potential complications of pruritus?

Because pruritus can be due to serious diseases, failure to seek treatment can result in serious complications and permanent damage. Once the underlying cause is diagnosed, it is important for you to follow the treatment plan that you and your health care professional design specifically for you to reduce the risk of potential complications including:

• Scarring
• Secondary skin infections due to scratching
• Spread of cancer
• Spread of infection
• Lesions on breast

References:

Itching. Medline Plus, a service of the National Library of Medicine National Institutes of Health. http://www.nlm.nih.gov/medlineplus/itching.html. Accessed May 26, 2011.

Itching. PubMed Health. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0003701/. Accessed May 26, 2011.