Causes of Itchy Skin and Treatment Options

Itchy skin can be frustrating, particularly if you don't know what is causing it or how to fix it. The medical term for itchiness is pruritus. It can be localized to a certain area of the body or can be all over (generalized).

If your itch is related to a rash, it's usually easy to determine what's causing it. The most difficult cases of itching skin, though, are those without a rash. This makes it harder to identify the source of the itch.

This article discusses what can cause itchy skin, how your healthcare provider can help determine what's causing it, and the types of treatments that can help bring you relief.

Itchy, Irritated Skin: What's Happening Inside Your Body

Itching occurs when nerve fibers in the skin send a message to the brain.

It may be caused by a local reaction to a substance or a systemic disease that triggers widespread (generalized) itchiness. In some cases, the cause may be psychological or even unknown (idiopathic).

Regardless of the cause, with itchiness comes a desire to scratch which often makes an itch worse (and leads to more scratching). This is called the itch-scratch cycle and is an important consideration in treating pruritis.

Localized Itchy Skin

When just one part of your body itches, it is usually caused by a problem in or on the skin. Where you itch can help give your healthcare provider clues about why.

Contact dermatitis and allergic dermatitis can occur anywhere on your body but are limited to the area of skin that came into contact with a particular allergen (like poison ivy) or irritative substance (like wool). Other conditions, such as eczema and psoriasis, can also cause localized itching on different body parts.

Causes of localized pruritus by body part include:

• Scalp: Head lice, seborrheic dermatitis
• Eyelids: Allergic conjunctivitis
• Nose: Allergic rhinitis (hay fever)
• Ears: Otitis externa (swimmer's ear)
• Trunk: Folliculitis, scabies
• Arms: Brachioradialis pruritis
• Legs: Xerosis (abnormally dry skin), dermatitis herpetiformis
• Hands and feet: Pompholyx, ringworm, scabies
• Groin or armpits: Tinea cruris (jock itch), yeast infections
• Anus: Pruritus ani, pinworms, hemorrhoids

Generalized Itchy Skin

While generalized itching can be caused by skin conditions like eczema or psoriasis, the prevalence of underlying systemic disease has been reported to be 10% to 50%. In some cases, the itching from these diseases will not have a tell-tale rash.

Some of the conditions that can cause generalized itching include:

• Allergic reactions, including anaphylaxis, urticaria ("hives"), drug allergies, and systemic dermatitis
• Demyelination (a type of nerve damage)
• Viral infections, such as mononucleosis, shingles or chickenpox
• Liver disease
• Iron deficiency
• Neuropathic itch, caused by nerve entrapment or degeneration 
• Thyroid disease, both hyperthyroidism and hypothyroidism
• Kidney disease, especially during dialysis
• Cancer, including leukemias and lymphomas
• Parasitic infections
• HIV, in both the early and late stages
• Pregnancy
  

Diagnosis

Treatment for itchy skin starts by identifying the underlying cause, whether a skin condition, an allergic reaction, or a disease that affects more than one body system (a systemic disease).

Talk to your provider if you have an itch (with or without a rash) that won't go away or if it interferes with your daily activities. You should also seek help if your rash is painful, blistering, or shows signs of infection.

Your healthcare provider will start with a careful history and perform a physical exam. They will examine your rash (if you have one) and look for signs of a more widespread problem.

You may need additional tests to identify what is causing your itch. These could include a complete blood count, HIV test, stool culture (to rule out parasites), or even a skin biopsy. They may also perform tests to assess how your liver, kidneys, or thyroid are functioning.

Treatment

The best way to stop an itch is to treat the cause. But sometimes, that takes time. Until the underlying problem is corrected, you may need treatment to control the itch and reduce the itch-scratch cycle.

Above all, do not scratch. Gently tapping your skin or applying cool cloths or ice packs to the itch can bring you some relief and avoid causing breaks in the skin that could get infected.

Non-specific treatments for itching include topical steroid creams, oral antihistamines (such as Benadryl), and changes to your skincare practices.

At-Home Itch Fix

Regardless of what's causing your itchy skin, some simple steps at home can help improve your symptoms, prevent dry skin, and reduce the urge to itch. These include:

• Don't take hot showers. Cooler, shorter showers are a better option.
• Use soap sparingly. Only apply soap to areas that need it, such as the groin, armpits, anal area, under the breasts, and other oily or dirty areas.
• Moisturize. Apply a moisturizing cream immediately after bathing.
• Avoid dry air. Humidify your home to at least 40%, especially during dry, cold months.
• Avoid irritants. Wool, fiberglass, detergents, or other topical irritants can aggravate your skin and make you itch.

If you continue to experience itchy skin, you should schedule an appointment with your healthcare provider.

Working With Your Doctor

Everyone has experienced an itching sensation—and an urgent need to scratch—at some point in their lives. Sometimes we know what's causing the itch (like a run-in with an allergen like poison ivy) but that isn't always the case.

Your healthcare provider can be a trusted ally in your efforts to stop your itch. They're able to:

• Help you identify the root cause (like an allergy or systemic disease).
• Provide insights into which treatments would be best (over-the-counter therapies or prescription medications).
• Guide you on steps you can take to minimize the itch-scratch cycle and avoid infection.

Having an action plan in place to treat whatever condition is causing your itch can help you streamline your medical appointments, avoid unnecessary tests, and give you peace of mind.

Summary

An uncontrollable itch can be maddening, especially if you aren't sure why it is happening or how to treat it. Itchy skin—or pruritus—can have a variety of causes, from contact with a skin irritant (like wool) to a more serious condition, so it's important to understand the reason behind your need to scratch.

Talk to your healthcare provider if you have an itch or rash that impacts your daily activities, doesn't go away, worsens over time, or shows signs of infection. Your provider will be able to help you take steps to reduce or eliminate your symptoms and keep them from coming back.