What laboratory work‑up, treatment regimen, and next steps are recommended for a 44‑year‑old woman with chronic generalized pruritus affecting the lower trunk and genital area, perimenopausal night sweats, and a history of severe contact dermatitis?

Laboratory Work-Up and Next Steps for Persistent Generalized Pruritus

This patient requires a comprehensive laboratory evaluation for generalized pruritus without underlying dermatosis (GPWOR), with particular attention to haematological causes given her night sweats, and should continue symptomatic antipruritic therapy while awaiting results.

Immediate Laboratory Testing Required

Based on the British Association of Dermatologists' 2018 guidelines for generalized pruritus, the following labs should be ordered now 1:

Essential First-Line Tests:

• Complete blood count with differential and blood film - to screen for polycythemia vera, lymphoma, and other haematological disorders
• Ferritin level - iron deficiency is a common cause of chronic pruritus (25% of pruritus with systemic disease responds to iron replacement) 1
• Comprehensive metabolic panel - including liver function tests (AST, ALT, alkaline phosphatase, bilirubin) and renal function (creatinine, BUN)
• Lactate dehydrogenase (LDH) - elevated in haematological malignancies
• Erythrocyte sedimentation rate (ESR) - helps evaluate for inflammatory/malignant processes

Important Clinical Context:

The combination of persistent pruritus with escalating night sweats is concerning for lymphoma 1. The guidelines specifically state: "Itching at night in association with weight loss, fevers and night sweats is suggestive of lymphoma" 1. While haematological causes account for only 2% of generalized pruritus cases, they must be ruled out given her symptom constellation.

Additional Recommended Tests:

• Thyroid function tests (TSH, free T4) - though not routinely recommended, reasonable given perimenopausal symptoms 1
• Tissue transglutaminase (TTG) antibodies - if iron deficiency is found 1
• Bile acids and antimitochondrial antibodies - if liver function tests are abnormal 1

Treatment Plan While Awaiting Results

Continue Current Effective Therapies:

Since she reported relief with the steroid dose pack and injection, continue the current regimen:

• Complete the Medrol dose pack as prescribed
• Continue hydroxyzine for both antihistamine effect and sleep aid
• Continue daily Zyrtec (cetirizine)
• Continue coconut oil topically

Add Neuropathic-Targeted Therapy:

Given the localized distribution (lower trunk, genital area, inner thighs, buttocks) and lack of visible dermatosis, this likely has a neuropathic component 2, 3. Add:

• Topical menthol or pramoxine cream to affected areas - effective for neuropathic pruritus 2
• Consider gabapentin 300 mg at bedtime, titrating up to 300 mg three times daily if needed - particularly effective for neuropathic pruritus 1, 2

Important Caveat About Allergy Testing:

Delay comprehensive allergy testing until 2-4 weeks after completing all systemic steroids to avoid false-negative results. However, given the history of severe contact dermatitis and genital involvement, patch testing will be important once steroids are cleared 4.

Red Flags Requiring Urgent Action

Refer immediately to haematology if labs show 1:

• Elevated haemoglobin/haematocrit (especially with microcytosis, elevated WBC or platelets, low ESR) - suggests polycythemia vera
• Elevated LDH with abnormal blood film
• Any lymphadenopathy on examination

Consider skin biopsy from trunk if 1:

• Pruritus persists despite treatment and negative systemic work-up
• Cutaneous lymphoma can present with normal-appearing skin and intense pruritus

Alpha-Gal Syndrome Testing

Proceed with alpha-gal testing as planned given:

• History of tick exposure at farm
• Persistent pruritus after environmental exposure
• This can be done concurrently with other testing

Follow-Up Timeline

• Labs within 1 week, review results within 2 weeks
• If all labs normal: Diagnosis is likely chronic pruritus of unknown origin (CPUO) or neuropathic pruritus 3
• If iron deficiency found: Trial of iron replacement (ferritin <15-25 μg/L or unexplained microcytic anemia) 1
• Allergy testing in 2-4 weeks after steroid completion
• Dermatology referral if no improvement after 4-6 weeks of treatment or if systemic therapy escalation needed 2

Common Pitfall to Avoid

Do not dismiss the night sweats as purely perimenopausal without ruling out haematological causes first. While hormonal fluctuations are likely contributing, the combination of severe pruritus + night sweats mandates haematological screening 1. The previous "normal" estrogen and progesterone levels do not exclude lymphoma or polycythemia vera.