Most Common Causes of Itching

Many insect bites can itch, including those from mosquitos, sandflies, fleas, fire ants, bed bugs, lice, flies, chiggers, and scabies. Most insect bites resolve on their own in a day or two, and you can care for them at home. Applying a cold, damp cloth to the bite can reduce swelling, and calamine lotion, baking soda paste, or hydrocortisone cream can soothe itching.

The main thing to look out for is anaphylaxis. Some people have severe allergic reactions to insect bites. If you experience difficulty breathing, swelling of the face or throat, hives, dizziness, or fainting after an insect bite, seek emergency medical attention.

Contact dermatitis occurs after the skin comes into contact with an irritant or allergen. The reaction does not always happen immediately and may not appear for up to 48 hours after exposure.

Many things can cause contact dermatitis, but some of the most common are soaps, detergents, perfumes, latex, fragrances, and plants like poison ivy, poison oak, or poison sumac. In addition to itching, symptoms include redness, swelling, blistering, and thick, scaly skin.

Itching is also a symptom of heat rash. Heat rash is more common in babies and children, but it can affect adults, too, especially in hot and humid climates.

Heat rash develops when sweat gets trapped against the skin. In infants, it usually develops on the chest, shoulders, and neck; in adults, it typically appears in skin folds and where clothing rubs against the skin. Heat rash can appear as small blisters or deeper red lumps; some types are very itchy.

Anyone can get hives, but they are more common in people with asthma and allergies. These raised red splotches or welts result from an allergic reaction.

Some hives are incredibly itchy, but they can also burn or sting. They vary significantly in size, ranging from as small as a pencil eraser to as large as a dinner plate. Most hives fade in 24 hours or so, but they may last for several days.

Atopic dermatitis or eczema is a condition that damages the skin's barrier layer, making it more sensitive. Eczema is more common in people with a history of asthma and allergies.

Infants are prone to getting eczema, but most outgrow it. Teens and adults with eczema get dry, bumpy, and itchy skin that can appear anywhere but is most common on the neck, hands, inner elbows, ankles, and feet. Eczema has no cure, and treatment aims at preventing flares and reducing discomfort.

Multiple fungal infections cause itching, including ringworm. Ringworm is an itchy red circular rash with a clear patch in the middle that typically appears on the trunk, arms, or legs. It is contagious and can spread from person to person or animal to person. You can also get ringworm from touching an object that an infected person or animal has come in contact with or from infected soil.

Ringworm is related to jock itch and athlete's foot, which also cause localized itchy rashes.

Itching is a side effect of many medications. Antifungals can cause an itchy red rash, and opioid pain medications can cause generalized itching.

Itching from antibiotics is a common sign that the person may be allergic to the medication and is more common with certain classes, like sulfa-based antibiotics and vancomycin.

The brain plays an essential role in the perception of itch, so much so that the symptom sometimes originates in the brain. Psychogenic itching is a disorder where the brain plays a role in triggering the itch or the intensity or persistence of the itch, and research shows it seems to be associated with depression or anxiety.

This phenomenon is poorly studied, but doctors believe it can be classified as a somatoform disorder, which is one where the patient has physical symptoms that a physical cause cannot explain.

Unexplained chronic itching can also result from an underlying neurological disease. A variety of conditions can lead to neuropathic itch, including stroke, peripheral nerve damage, shingles, spinal cord lesions, cranial nerve damage, and phantom pain in amputated body parts.

Treatment of neurogenic itching can be complex. Common options include Botox injections, pain medications, antiseizure medications, neurostimulation, and wrapping the affected area to prevent scratching injuries.

Sometimes, itching is a sign of a systemic condition. People with advanced kidney and liver diseases often experience generalized itching, as do those with endocrine disorders like hyperthyroidism, hypothyroidism, diabetes, Cushing syndrome, Addison's disease, and polycystic ovarian syndrome.

Anemia can cause itching, as can more severe conditions like cancer and HIV. Some people with chronic heart failure also experience itching.

Dry skin, medically known as xerosis, is a frequent culprit behind the nagging itch many people experience. Particularly prevalent during the colder months or in areas with low humidity, this condition leads to a tight, uncomfortable sensation on the skin. Older adults are especially prone to dry skin due to the natural decrease in oils and moisture in their skin over time. You can combat dry skin and potentially achieve significant relief by incorporating a daily regimen of hydrating moisturizers, using gentle, nonirritating cleansers, and opting for lukewarm baths. It also helps to avoid harsh, drying soaps and apply moisturizer immediately after bathing to lock in moisture.

The journey of pregnancy brings about a myriad of changes, not least of which is the skin's tendency to itch as it stretches to accommodate the growing baby. Primarily due to hormonal fluctuations and the skin's physical expansion, this itching typically occurs especially around the abdomen, thighs, and breasts. While this sensation is generally harmless and part of the natural process of pregnancy, it's important for expectant mothers to monitor their symptoms. In rare cases, severe itching without a rash, particularly in the third trimester, could signal obstetric cholestasis, a liver condition that requires medical attention. Moisturizers and loose-fitting clothing can offer relief, but you should discuss persistent or severe itching with a healthcare provider.