What is the appropriate diagnosis and treatment for an elderly female patient with microcytosis, elevated ESR and CRP, a rash on the forehead, and tenderness to the occipital scalp?

Giant Cell Arteritis (GCA) with Scalp Tenderness and Elevated Inflammatory Markers

This elderly female patient requires immediate temporal artery biopsy and high-dose glucocorticoid therapy (prednisone 40-60 mg daily) for presumed giant cell arteritis, given the combination of scalp tenderness, forehead rash along the hairline, markedly elevated ESR (80) and CRP (26), even in the absence of classic temporal artery tenderness. 1

Clinical Presentation Analysis

The patient's presentation is highly concerning for GCA based on several key features:

• ESR of 80 mm/h: This exceeds the diagnostic threshold of >40 mm/h, which has 93.2% sensitivity for GCA with a negative likelihood ratio of 0.18 2, 3
• CRP of 26: Markedly elevated, and CRP has 97.5% sensitivity for GCA 4, 3
• Scalp tenderness: A cardinal cranial manifestation of GCA 1
• Forehead rash with tenderness along hairline: Consistent with superficial temporal artery involvement 1
• Age and gender: Elderly female fits the typical demographic (>50 years, more common in women) 1

The absence of temporal artery tenderness does not exclude GCA, as scalp tenderness alone is sufficient 1. The occipital scalp tenderness further supports cranial arteritis 1.

Microcytosis Interpretation

The microcytosis (MCV 72) without anemia (Hgb 12.6) represents trending iron deficiency or early anemia of chronic disease from the underlying inflammatory process:

• The elevated ESR and CRP with microcytosis suggests chronic inflammation causing iron sequestration 5
• This pattern is consistent with functional iron deficiency from inflammatory states 5
• This finding does not change the urgency of GCA evaluation but explains the hematologic abnormality 5

Immediate Diagnostic Workup

Temporal Artery Biopsy

• Perform temporal artery biopsy urgently (ideally within 1-2 weeks, but do not delay treatment) 1
• The biopsy can be performed after starting glucocorticoids, as histologic changes persist for weeks 1, 6
• Negative biopsy does not exclude GCA if clinical suspicion remains high 6, 4

Additional Testing

• Ophthalmology referral immediately to assess for visual symptoms or subclinical involvement 1
• Check for jaw claudication (ask specifically about pain with chewing) 1
• Assess for constitutional symptoms (fever, weight loss, malaise) 1
• Evaluate for polymyalgia rheumatica symptoms (bilateral shoulder/hip pain, morning stiffness >45 minutes) 1, 7

Treatment Protocol

Glucocorticoid Therapy

Initiate prednisone 40-60 mg daily immediately without waiting for biopsy results 1, 5, 7:

• High-dose therapy is critical to prevent irreversible vision loss from anterior ischemic optic neuropathy 6, 8
• Symptom relief should occur within 24-72 hours, which reinforces the diagnosis 7
• Do not use lower doses (such as 20 mg) initially, as this is inadequate for cranial GCA 1, 7

Monitoring Strategy

• ESR and CRP every 2-4 weeks initially until normalization 1, 5
• After normalization, taper prednisone gradually while monitoring for symptom recurrence 7
• Continue monitoring ESR/CRP every 6 months during maintenance therapy 5
• Most patients require 2-3 years of treatment 7

Glucocorticoid-Sparing Agents

• Consider tocilizumab (FDA-approved for GCA) or other immunosuppressive agents to reduce glucocorticoid exposure 1
• The 2021 ACR/Vasculitis Foundation guideline supports glucocorticoid-sparing agents in GCA 1

Critical Pitfalls to Avoid

1. Do not wait for temporal artery biopsy results before starting treatment - vision loss can occur rapidly and is irreversible 1, 6

2. Do not dismiss GCA based on absence of temporal artery tenderness - scalp tenderness and occipital involvement are sufficient cranial manifestations 1

3. Do not use both ESR and CRP being normal to exclude GCA - while rare (0.8% of cases), GCA can present with normal inflammatory markers 4, 3

4. Do not attribute symptoms solely to the recent chills/infection - the combination of scalp tenderness, rash along hairline, and markedly elevated inflammatory markers demands GCA evaluation 1, 2

5. Do not start with lower prednisone doses (10-20 mg) appropriate for polymyalgia rheumatica - cranial GCA requires 40-60 mg daily 1, 7

Concordance of Inflammatory Markers

The concordantly elevated ESR and CRP increases diagnostic certainty with an odds ratio of 3.06 for positive temporal artery biopsy 3. Only 1.7% of GCA patients have elevated ESR with normal CRP, and only 4% have both markers normal at diagnosis 4, 3. This patient's markedly elevated values (ESR 80, CRP 26) strongly support the diagnosis 2, 3.

Large Vessel Involvement Assessment

Consider imaging for large vessel involvement, as the 2021 ACR guideline supports using imaging to identify extracranial disease 1:

• Check peripheral pulses and blood pressure in both arms 1
• Consider vascular imaging if symptoms suggest large vessel involvement (limb claudication, absent pulses) 1