Answers to why you itch all over

It's hard to get through daily activities when you itch all over. The widespread discomfortknown as generalized itchingis distracting and frustrating. When its cause is unclearit's difficult to know how to find relief.

To help navigate this challengewe turned to Dr. Martina Portera dermatologist at Harvard-affiliated Beth Israel Deaconess Medical Center.

Q. How concerning is generalized itching?

A. Dr. Porter: It's something that we take seriously. It can have an extremely negative impact on someone's quality of lifeparticularly if it disturbs sleep.

Q. How common is the condition?

A. Dr. Porter: It's much more common than you'd expect. An estimated 8% to 16% of the total population can report having generalized itching in the past 12 months. And about 20% of the population will experience generalized itching in their lifetime.

Q. What causes generalized itching?

A. Dr. Porter: Generalized itching can be caused by dry skinsevere cases of certain skin conditionsor skin changes that occur with age. Widespread itching might also be due to conditions that don't have obvious signs on the skin. Examples include diabetesthyroid diseasekidney diseaseliver diseasecancerblood disordersnerve-related causesand some psychiatric conditions. HIV infection and medications can also cause itchas can pregnancy.

Q. How do you pinpoint the cause when it isn't obvious?

A. Dr. Porter: That requires a bit of detective work. We take a thorough health historyask about all signs and symptomsand examine all of the skin. We check the lymph nodes to see if they're swollen: if sothat could be a sign of cancer or an infection. We consider the distribution of itching to figure out if this is really generalized all-over itchingwhich points to an internal causeor just localized itchingwhich is usually due to an exposure the body is reacting to or a nerve-related cause. When it is generalized itchingwe usually order blood tests to help identify suspected internal causes. Some people may also need imaging tests to look for signs of canceralthough that's rare.

It can take time to identify the causebut we still try to treat the itch while we investigate.

Q. What are treatments for generalized itching?

A. Dr. Porter: Treatment must be tailored to the underlying condition causing generalized itching. So if you have diabetes or thyroid diseasewe need to treat that. We might also prescribe topicaloralor injectable medications to help with the itchor phototherapy that uses properties of ultraviolet light to decrease inflammation and itch.

Sometimes people are tempted to try and treat itching at home by taking antihistaminessuch as diphenhydramine [Benadryl]loratadine [Claritin]fexo­fenadine [Allegra]or cetirizine [Zyrtec]. These medications can be helpful for hives or allergic causes of itchingbut we try to limit their use for generalized itching in older people because of a potential increased risk of dementia.

Q. Are any home remedies helpful?

A. Dr. Porter: Dry skin can be very itchywhich makes generalized itching worse. So it is important to moisturizeparticularly in the colderless humid winter months.

For those who suffer from very dry skin or eczemawe recommend specific showering and bathing techniquessuch as using lukewarm rather than hot water; using soap only on the armpitsgenitalsfeetand face; and moisturizing everywhere immediately after bathing before your skin has a chance to fully dry.

There are many over-the-counter options for moisturizersand some contain mentholpramoxinecamphoror capsaicin. Those ingredients can help alter nerve signaling and may decrease itch signals - although some ingredients may instead cause a burningnumbingor cooling sensation. Applying over-the-counter 1% hydro-cortisone cream or ointment can help calm mild inflammation if itching is worse in a particular spot.

Q. Is it possible to stop the itch?

A. Dr. Porter: Yes. You don't have to suffer with constant itching. Make an appointment with a dermatologist. Be sure to tell the doctor where the itching is occurring. And try some home remedies until your visit.

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