What causes itchy skin all over?

The most common cause of all-over itching by far is dry skin - especially in winter, after hot showers, with central heating, and as skin ages. After that, the list splits into two groups. Itch WITH visible changes points to skin conditions: eczema, hives, scabies (itch worse at night with burrows between fingers), psoriasis, or contact allergy to a new detergent or soap. Itch with NO rash is the one to take seriously beyond the bathroom cabinet, because generalized itch can be the first sign of an internal problem: thyroid disease, liver problems (often with yellowing eyes), kidney disease, iron deficiency anemia, uncontrolled diabetes, or - less commonly - blood disorders. Medications can do it too, opioids and some blood pressure drugs among them. Practical relief while you sort it out: lukewarm short showers, fragrance-free moisturizer within minutes of drying off, gentle detergent, cool rooms, cotton against the skin, and short nails. See a doctor if itch lasts more than two weeks despite moisturizing, is severe enough to wreck sleep, comes with weight loss, fatigue, fever, or yellowing skin or eyes, or if a new medicine started around the same time - a few blood tests answer most of the internal causes. Pymander is a free AI doctor, 24/7 by text, that can help you map your pattern.