Etiology

1. Skin Conditions:

   • Dermatitis: This includes contact dermatitis, atopic dermatitis (eczema), and seborrheic dermatitis.
   • Psoriasis: A chronic skin condition characterized by red, scaly patches.
   • Urticaria (Hives): Itchy, raised welts on the skin that can be triggered by allergies or other factors.
   • Fungal Infections: Such as ringworm, athlete's foot, or candidiasis.
   • Parasitic Infections: Such as scabies or lice.

2. Allergies:

   • Allergic reactions to foods, medications, insect bites, or latex.

3. Systemic Diseases:

   • Liver Disease: Pruritus can be associated with liver conditions like cholestasis.
   • Kidney Disease: Uremic pruritus is a symptom of advanced kidney disease.
   • Thyroid Disorders: Especially hypothyroidism.
   • Hematologic Disorders: Such as polycythemia vera.
   • Malignancies: Some cancers, like lymphoma or leukemia, can cause itching.
   • Iron Deficiency Anemia: Can sometimes lead to pruritus.

4. Neurological Causes:

   • Nerve disorders, such as neuropathy, can lead to itching.

5. Psychological Factors:

   • Stress, anxiety, and depression can worsen itching or even be the primary cause.

6. Medications:

   • Certain drugs, including opioids, can cause pruritus as a side effect.

7. Autoimmune Conditions:

   • Conditions like lupus or Sjögren's syndrome can lead to skin and systemic symptoms, including itching.

8. Infectious Diseases:

   • Infections like HIV or hepatitis C can cause pruritus.

9. Metabolic Disorders:

   • Conditions like diabetes or thyroid disorders may be associated with itching.

10. Hormonal Changes:

    • Hormonal fluctuations, such as those during pregnancy or menopause, can lead to itching.

11. Environmental Factors:

    • Exposure to irritants, such as chemicals or extreme temperatures, can cause itching.

12. Idiopathic Pruritus:

    • In some cases, the cause of itching remains unknown (idiopathic pruritus).

Making the Diagnosis and Management_Adult

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