Differential Diagnosis for Itching on the Scalp and Full Body
- Single most likely diagnosis
- Dry skin (xerosis): This is a common condition that can cause itching all over the body, including the scalp. It's especially prevalent in dry environments or during winter months. The recent onset of symptoms could be due to a change in environment, soap, or shampoo.
- Other Likely diagnoses
- Eczema (atopic dermatitis): A chronic condition characterized by itchy, inflamed skin. It can affect any part of the body, including the scalp, and is often associated with allergies or asthma.
- 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. It can affect the scalp and spread to other parts of the body.
- Allergic contact dermatitis: A reaction that occurs after skin comes into contact with an allergen or irritant, leading to itching, redness, and small bumps. This could be due to a new shampoo, soap, or other product.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed)
- Hodgkin lymphoma: Although rare, some types of lymphoma can cause severe itching all over the body without any visible rash. It's crucial to consider this in the differential diagnosis due to its serious implications.
- Thyroid disorders: Both hyperthyroidism and hypothyroidism can cause itching, although the mechanism is not fully understood. These conditions have significant health implications if left untreated.
- Kidney or liver disease: Certain diseases affecting these organs can lead to itching due to the buildup of toxins in the blood. Early detection is critical for effective management.
- Rare diagnoses
- Pityriasis rosea: A skin condition characterized by a rash that can cause itching, often starting with a single patch on the trunk and spreading. It's more common in younger adults.
- Scabies: A parasitic infection caused by the mite Sarcoptes scabiei, leading to intense itching, especially at night, and a pimple-like skin rash. It's contagious and can spread quickly in crowded areas.
- Cutaneous T-cell lymphoma (Mycosis fungoides): A rare type of skin cancer that can cause itching, among other symptoms. It often mimics more benign skin conditions, making diagnosis challenging.