1. Dermatological examination:
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- Clinical distribution of pruritic lesions (e.g., localized/generalized; symmetrical/asymmetrical) |
- Dermatological morphology of pruritic lesions; |
- Number of affected body regions; number of pruritic lesions/with excoriated lesions on top |
- Butterfly sign (area spared from lesions or excoriations on the back, where the patient's hands cannot reach) |
2. Objective methods:
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- Measurement of pruritic lesions (with a ruler or another equipment); |
- Monitoring a target lesion when possible (clinically or through photographs); |
- Photographic documentation; |
- Scores: IGA, for the staging of chronic prurigo |
3. Overall physical examination:
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- Abdominal palpation, assessment of lymphadenopathy, assessment of muscle strength, auscultation (lungs, heart, abdomen) |
- Simple neurological examination; |
- Dermatological examination: presence of concomitant skin diseases, xerosis, inspection of mucous membranes; |
- Dermoscopy of pruritic lesions (searching for ectoparasites such as Sarcoptes scabiei); |
- Dermographism assessment; Nikolsky sign testing; Darier sign testing. |
II. SKIN BIOPSY/FLUIDS and BLOOD EXAMS:
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1. Skin biopsies |
2. Fluids/microbiological culture when there are signs of infection |
3. Direct microscopic evaluation: screening for Sarcoptes scabiei
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- Direct and indirect immunofluorescence (when autoimmune conditions such as bullous pemphigoid, dermatitis herpetiformis, linear IgA dermatosis, paraneoplastic pemphigus, etc. are suspected). |
- Histopathology (hematoxylin-eosin staining or histochemistry for amyloid, mucin and other cutaneous deposits) |
III. COMPLEMENTARY DIAGNOSTIC EXAMS
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1. Avoid invasive diagnostic procedures, if unnecessary, for:
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- CPG with pruritus of mild intensity or small extent; |
- CPG of non-dermatological origin; |
- Elderly, pediatric and frail patients. |
2. Groups of patients in whom imaging and laboratory studies are recommended:
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- With a family history |
- With a medical history (e.g. presence of bloody sputum, change in cough profile) |
- Rule out underlying diseases in all patients with CPG |
- In all patients with CPG duration of at least one year |
- In patients with CPG who report night sweats, or weight loss |
- In patients with CPG of undetermined origin |
- In CPG patients with disproportionate pruritus |
- When patients demand laboratory tests |
3. Regularly performed laboratory tests:
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- Blood count; electrolytes, ESR, CRP, fasting blood glucose, glycated hemoglobin (HbA1c), iron, ferritin, LDH, TSH |
- Total serum IgE, specific IgE (if respiratory or ocular allergy is suspected) |
- Renal retention parameters (e.g., potassium, creatinine, urea, glomerular filtration rate) |
- Liver enzymes (e.g., gamma-GT, AST, ALT, alkaline phosphatase, bilirubin) |
4. Laboratory tests - based on pathological findings or medical history :
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- Serum and urinary protein electrophoresis, immunofixation (increased sensitivity if monoclonal gammopathy is suspected) |
- Flow cytometry immunophenotyping for hematological malignancies in peripheral blood
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- Serum tryptase (if systemic mastocytosis is suspected) |
- Diagnosis of thyroidopathy in special situations (e.g., parathyroid hormone, phosphate, Ca2+, fT3, fT4). |
- Vitamin B12, folic acid (if anemia is present). |
5. Imaging exams, if the history and physical examination are suggestive of neoplasia or systemic diseases:
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- Computed tomography (CT) of the skull, chest and abdomen; digestive endoscopy, colonoscopy |