Dry Skin (Xerosis): This is often the most common cause of generalized itching, especially in older adults or during dry weather conditions. It's a benign condition but can significantly affect quality of life.

Atopic Dermatitis (Eczema): A chronic skin condition characterized by itchy, inflamed skin. It's common in individuals with a history of allergies or asthma.
Allergic Reactions: Can be due to various allergens such as drugs, foods, or contact allergens, leading to generalized itching.
Psoriasis: An autoimmune condition that speeds up the life cycle of skin cells, causing cells to build up rapidly on the surface of the skin. The extra skin cells form scales and red patches that itch or burn.
Urticaria (Hives): Characterized by itchy, raised welts on the skin, often due to allergic reactions but can also be caused by infections or autoimmunity.

Hodgkin Lymphoma: A type of lymphoma that can present with generalized itching as an early symptom, often without any other significant findings.
Chronic Kidney Disease: Itching can be a symptom of advanced kidney disease due to the buildup of toxins in the blood.
Hypothyroidism: Some patients with hypothyroidism may experience generalized itching due to dry skin or other metabolic changes.
Liver Disease (Cholestasis): Itching can be a symptom of liver diseases that affect bile flow, such as primary biliary cirrhosis.

Polycythemia Vera: A rare blood disorder that can cause itching, especially after warm baths or showers, due to the release of histamine from basophils.
Thyroid Storm: A life-threatening complication of untreated or undertreated hyperthyroidism, which can present with itching among other severe symptoms.
Neurological Disorders: Certain rare neurological conditions, such as multiple sclerosis or peripheral neuropathy, can cause itching sensations without a clear skin cause.
Parasitic Infestations: Such as scabies or lice, which can cause severe itching, especially at night.