What is the cause of chronic generalized pruritus (itching) without rash in an elderly female with normal laboratory tests, normal allergy workup, and a history of breast implants?

Chronic Generalized Pruritus Without Rash in an Elderly Female

The most likely causes in this patient are iron deficiency, occult malignancy (particularly lymphoma), or chronic pruritus of unknown origin, and the breast implants are unlikely to be the culprit. 1, 2

Systematic Diagnostic Approach

Initial Laboratory Evaluation

The British Association of Dermatologists recommends specific initial investigations for all patients with chronic generalized pruritus without rash 1:

• Complete blood count with differential - to evaluate for hematologic malignancy (lymphoma, polycythemia vera) or anemia 1, 3
• Ferritin levels AND complete iron studies (serum iron, total iron binding capacity) - iron deficiency is a common and treatable cause of generalized pruritus, and ferritin can be falsely elevated as an acute-phase protein despite true iron deficiency 1, 2
• Liver function tests - cholestatic liver disease is a major cause of generalized pruritus 1, 4
• Urea and electrolytes/creatinine - chronic kidney disease and uremia are well-established causes 1, 5
• Thyroid function tests - only if clinical features suggest thyroid disease (not routine) 6

Critical Caveat About "Normal Labs"

If ferritin appears "normal" but iron deficiency is still suspected clinically, serum iron and total iron binding capacity must be checked, as ferritin can be misleadingly normal. 2 Additionally, both iron deficiency AND iron overload can cause generalized pruritus, so the complete iron panel is essential 1, 2.

Most Likely Etiologies in This Patient

1. Iron Deficiency (Most Common Treatable Cause)

• Iron deficiency anemia causes generalized pruritus in many patients, with iron replacement therapy leading to complete cessation of pruritus shortly after treatment begins 1, 2
• This is particularly important in elderly females who may have occult gastrointestinal blood loss or poor dietary intake 2
• Treatment: Iron replacement therapy if deficiency is confirmed 1, 2

2. Occult Malignancy (Highest Morbidity/Mortality Risk)

• Hodgkin lymphoma is the malignancy most strongly associated with pruritus, affecting up to 30% of patients with the disease 3, 7
• Solid tumors and polycythemia vera can also present with generalized pruritus 1, 5
• Chest radiography should be obtained when lymphoma is suspected 3
• The British Association of Dermatologists recommends that investigations be guided by thorough history and physical examination, though full malignancy workup is not routinely recommended unless systemic symptoms are present 6
• Consider JAK2 V617F mutation analysis if polycythemia vera is suspected (particularly if aquagenic pruritus is present) 1

3. Chronic Pruritus of Unknown Origin

• This accounts for approximately 15% of chronic pruritus cases when systemic diseases are excluded 5
• Often has a neuropathic component 5

What About the Breast Implants?

The breast implants are unlikely to be causing generalized pruritus. While breast implant illness is a controversial entity, generalized pruritus without rash for 6 months is not a characteristic presentation. The systematic evaluation should focus on the well-established causes outlined above 1, 4.

Additional Investigations to Consider

If initial workup is unrevealing 1:

• HIV and hepatitis serology - if appropriate travel or risk history 1
• Skin biopsy - for persistent unexplained pruritus to evaluate for cutaneous lymphoma or small fiber neuropathy 1
• Tissue transglutaminase antibodies - if iron deficiency is unexplained (celiac disease) 2

Treatment Approach While Investigating

Symptomatic Management

• Topical neuropathic agents (menthol, pramoxine, or lidocaine) can be used for neuropathic or mixed etiology pruritus 5
• Long-acting antihistamines (cetirizine, loratadine, fexofenadine) may provide some relief, though pruritus without urticaria is often histamine-independent 3
• Liberal emollient use and limiting water exposure 4

If Paraneoplastic Pruritus is Suspected

• Paraneoplastic pruritus may be relieved with paroxetine, mirtazapine, granisetron, or aprepitant 6

For Neuropathic Component

• Gabapentin, antidepressants (sertraline, doxepin), or opioid receptor agonist/antagonists (naltrexone, butorphanol) are effective for neuropathic pruritus 5

Common Pitfall

The most critical pitfall is accepting "normal labs" at face value without verifying that comprehensive iron studies (not just ferritin alone) and all recommended screening tests were actually performed. 2 Many patients with iron deficiency and pruritus have been missed because only ferritin was checked, which appeared falsely normal 2.