A 78‑year‑old woman with primary or secondary adrenal insufficiency on prednisone 40 mg daily presents with random fern‑like skin lesions; how should these lesions be evaluated and managed?

Evaluation and Management of Skin Lesions in a Patient on Supraphysiologic Prednisone

Immediate Priority: Address Glucocorticoid Over-Replacement

This 78-year-old woman is receiving 40 mg prednisone daily—a dose that is 8-10 times higher than the recommended replacement range for adrenal insufficiency and represents severe iatrogenic glucocorticoid excess, not physiologic replacement therapy. 1, 2

The "random fern-like skin lesions" (likely referring to striae or other glucocorticoid-induced skin changes) are almost certainly manifestations of chronic glucocorticoid toxicity from this supraphysiologic dose. 1

Algorithmic Approach to Management

Step 1: Confirm the Diagnosis of Adrenal Insufficiency

• Review the original diagnostic workup to verify that adrenal insufficiency was properly diagnosed with morning cortisol and ACTH measurements or cosyntropin stimulation testing 1, 2
• If no prior diagnostic confirmation exists, do not attempt testing while the patient remains on prednisone—the exogenous steroid will suppress the HPA axis and yield false results 2, 3

Step 2: Immediately Reduce to Physiologic Replacement Dosing

The correct replacement dose for confirmed adrenal insufficiency is:

• Prednisone 4-5 mg daily (taken as a single morning dose), OR 1
• Hydrocortisone 15-25 mg daily in divided doses (typically 10 mg at 7:00 AM, 5 mg at 12:00 PM, and 2.5-5 mg at 4:00 PM) 1, 4

Prednisolone 4-5 mg daily should only be considered in select patients who experience marked fluctuations in energy or when hydrocortisone is not tolerated. 1

Step 3: Add Mineralocorticoid Replacement if Primary Adrenal Insufficiency

• If the patient has primary adrenal insufficiency (autoimmune, adrenoleukodystrophy, tuberculosis, hemorrhage), add fludrocortisone 50-200 µg daily taken in the morning 1, 5
• Advise unrestricted salt and salty food intake, avoiding potassium-containing salt substitutes 1, 5
• Secondary adrenal insufficiency does not require mineralocorticoid replacement 5, 6

Step 4: Evaluate the Skin Lesions After Dose Correction

Signs of glucocorticoid over-replacement include:

• Weight gain (particularly truncal and facial) 1, 4
• Peripheral edema 1, 4
• Insomnia 1, 4
• Skin changes: striae, easy bruising, thin fragile skin, poor wound healing 1

After reducing to physiologic replacement doses, reassess the skin lesions in 2-4 weeks:

• Many glucocorticoid-induced skin changes will improve or stabilize once excess exposure is eliminated 1, 4
• If lesions persist or worsen despite appropriate dosing, consider dermatology referral for biopsy to exclude other etiologies 1

Step 5: Monitor for Signs of Under-Replacement

After dose reduction, watch for symptoms requiring dose adjustment:

• Lethargy, nausea, poor appetite, weight loss, increased pigmentation (primary AI only) indicate under-replacement 1, 2, 4
• Morning nausea can be relieved by taking the first dose earlier and returning to sleep 1, 2

Step 6: Essential Patient Education

All patients with adrenal insufficiency must receive:

• Medical alert bracelet or necklace indicating adrenal insufficiency 1, 2
• Steroid emergency card 1, 2
• Injectable hydrocortisone 100 mg IM kit with self-injection training 1, 2, 6
• Stress-dosing instructions: double or triple the dose during fever, infection, or minor illness 2, 4, 6
• Immediate emergency care instructions: for vomiting, severe illness, or inability to take oral medications 2, 6, 7

Critical Pitfalls to Avoid

Never continue supraphysiologic glucocorticoid doses (>7.5 mg prednisone equivalent) for chronic adrenal insufficiency replacement—this causes iatrogenic Cushing's syndrome with serious complications including osteoporosis, diabetes, cardiovascular disease, and skin fragility. 1, 4, 6

Never abruptly discontinue glucocorticoids in confirmed adrenal insufficiency—this will precipitate life-threatening adrenal crisis. 1, 2, 6

Never delay treatment of suspected adrenal crisis for diagnostic procedures—if the patient develops hypotension, altered mental status, or severe vomiting, give hydrocortisone 100 mg IV immediately plus 0.9% saline infusion at 1 L/hour. 1, 2, 6

Drug Interactions Requiring Dose Adjustment

Medications that increase glucocorticoid requirements:

• Anticonvulsants (phenytoin, carbamazepine, phenobarbital) 1, 4
• Rifampin and other antituberculosis drugs 1, 4
• Topiramate 1

Substances that decrease glucocorticoid requirements (avoid or reduce dose):

• Grapefruit juice 1, 4
• Licorice 1, 4

For primary adrenal insufficiency, avoid medications that interfere with fludrocortisone:

• Diuretics, acetazolamide, NSAIDs, carbenoxolone 1, 5
• Drospirenone-containing contraceptives may require fludrocortisone dose increase 1, 5

Follow-Up Monitoring

Annual review should include:

• Assessment of weight, blood pressure (supine and standing), and presence of peripheral edema 1, 5
• Serum electrolytes (sodium, potassium) 1
• Screening for new autoimmune disorders (thyroid function, diabetes, celiac disease, pernicious anemia) 2, 6
• Bone mineral density every 3-5 years to assess for glucocorticoid-induced osteoporosis 1