Differential Diagnosis for Itching
- Single most likely diagnosis
- Dry skin (xerosis): This is often the most common cause of itching, especially in older adults or during dry weather, due to the lack of moisture in the skin.
- Other Likely diagnoses
- Eczema (atopic dermatitis): A chronic condition characterized by itchy, inflamed skin, often associated with allergies or asthma.
- Allergic reactions: Itching can be a symptom of an allergic reaction to substances like insect bites, certain foods, or medications.
- 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, leading to itching and other symptoms.
- Insect bites or stings: Itching is a common reaction to bites or stings from insects like mosquitoes, fleas, or bed bugs.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Malignancy (e.g., lymphoma): In some cases, itching can be a symptom of an underlying malignancy, making it crucial to investigate further if other symptoms or risk factors are present.
- Liver disease: Severe itching can be associated with liver conditions such as primary biliary cirrhosis or liver cancer.
- Thyroid disorders: Both hyperthyroidism and hypothyroidism can cause itching due to changes in skin metabolism and dryness.
- Rare diagnoses
- Neurological conditions (e.g., multiple sclerosis, neuropathy): Itching can be a symptom of certain neurological disorders, often due to nerve damage or dysfunction.
- Kidney disease: Itching can occur in patients with chronic kidney disease, possibly due to the buildup of toxins in the blood.
- Parasitic infections (e.g., scabies, lice): While not as common in some regions, parasitic infections can cause severe itching and should be considered, especially in outbreaks or in individuals with poor hygiene or living in crowded conditions.