Dry Skin (Xerosis): This is often the most common cause of chronic itching, especially in older adults or during dry weather. Itching can be widespread and is usually worse in the winter.

Atopic Dermatitis (Eczema): A chronic skin condition characterized by itchy, inflamed skin. It often starts in childhood but can persist into adulthood.
Allergic Contact Dermatitis: An allergic reaction to substances like metals, fragrances, or dyes in clothing, leading to itchy skin.
Psoriasis: An autoimmune condition causing red, itchy, scaly patches on the skin.
Urticaria (Hives): Itchy welts that can appear anywhere on the body, often due to allergic reactions or infections.
Insect Bites or Infestations: Such as scabies or bed bugs, which can cause intense itching.

Hodgkin Lymphoma: A type of cancer that can cause itching without a rash, often accompanied by other symptoms like weight loss or fever.
Chronic Kidney Disease or Liver Disease: Itching can be a symptom of these conditions due to the buildup of toxins in the body.
Thyroid Disorders: Both hyperthyroidism and hypothyroidism can cause itching, among other symptoms.
Multiple Myeloma: A type of blood cancer that can cause itching due to the high levels of proteins in the blood.

Polycythemia Vera: A rare blood disorder that can cause itching, especially after warm baths or showers.
Neurological Disorders: Such as multiple sclerosis or peripheral neuropathy, which can cause itching sensations without a rash.
Parasitic Infections: Certain parasites like hookworms can cause itching, especially on the feet.
Brachioradial Pruritus: A rare condition causing intense itching on the arms, often without a rash, and can be related to nerve damage or cervical spine conditions.