In a 28-year-old woman presenting with bilateral purple striae on the anteromedial thighs for 2 months, constant sweating, and a 6 kg weight gain over 3 months, what is the most likely diagnosis and the recommended treatment regimen with dosages?

Diagnosis: Cushing's Syndrome

This 28-year-old woman presenting with purple striae, rapid weight gain (6 kg over 3 months), and constant sweating has a clinical picture highly suggestive of Cushing's syndrome and requires immediate biochemical screening.

Clinical Reasoning

The combination of reddish-purple striae (particularly wide striae on the thighs), rapid weight gain, and sweating in a young woman represents a constellation of features with high discriminatory value for Cushing's syndrome 1. Purple striae are among the most specific clinical features of hypercortisolism, especially when appearing in unusual locations and in a young patient 1, 2, 3. The rapid 6 kg weight gain over 3 months with constant sweating further supports this diagnosis.

Diagnostic Workup

Initial Screening (Choose ONE of the following):

• 24-hour urinary free cortisol measurement
• Late-night salivary cortisol (two measurements)
• 1 mg overnight dexamethasone suppression test

1

Critical first step: Exclude exogenous glucocorticoid exposure before any biochemical testing - obtain thorough medication history including topical creams, herbal preparations, injections, and megestrol acetate 1.

If Screening is Positive:

1. Measure plasma ACTH to distinguish ACTH-dependent from ACTH-independent causes 3
2. MRI of pituitary if ACTH-dependent
3. Bilateral inferior petrosal sinus sampling with ACTH-releasing hormone stimulation to differentiate pituitary from ectopic ACTH secretion 3
4. Adrenal imaging (CT or MRI) if ACTH-independent

Treatment Approach

First-Line Treatment:

Surgical resection of the causative lesion is the primary treatment 4:

• Transsphenoidal selective adenomectomy for pituitary adenomas (Cushing's disease)
• Unilateral adrenalectomy for adrenal adenomas
• Resection with node dissection for ectopic ACTH-secreting tumors

4

Medical Therapy (Second-Line or Bridge to Surgery):

Ketoconazole is the medical treatment of choice 3:

• Starting dose: 200 mg twice daily
• Titrate up to 400-600 mg twice daily (maximum 1200 mg/day)
• Monitor liver function tests every 2 weeks initially, then monthly
• Alternative: Cabergoline can be added (as demonstrated effective in case reports 5)

Perioperative Management:

• Venous thromboembolism prophylaxis is essential perioperatively 4
• Stress-dose glucocorticoid coverage post-operatively
• Vaccinations: Influenza, Herpes zoster, and pneumococcal vaccines due to immunosuppression 4

Comorbidity Management (Essential Concurrent Treatment):

Treat all cortisol-dependent complications 4:

• Hypertension: Antihypertensives as needed
• Hyperglycemia: Diabetes management if present
• Hypokalemia: Potassium supplementation and/or spironolactone
• Osteoporosis screening: DEXA scan and bisphosphonates if indicated
• Psychiatric symptoms: Appropriate psychiatric support
• Infection prophylaxis: Due to immunosuppression

Critical Pitfalls to Avoid:

1. Do not treat based on clinical suspicion alone - biochemical confirmation is mandatory before initiating cortisol-lowering therapy 4
2. Do not miss iatrogenic causes - thoroughly exclude exogenous glucocorticoids including injections, topical preparations, and herbal supplements 1, 6
3. Do not delay surgical referral - medical therapy is temporizing; definitive treatment requires tumor resection 4
4. Do not overlook thromboembolism risk - these patients have significantly elevated VTE risk requiring prophylaxis 4

Multidisciplinary Approach Required:

Management requires coordination between endocrinology, neurosurgery (for pituitary lesions) or general surgery (for adrenal lesions), and primary care for comorbidity management 4. Patient education about disease course, treatment expectations, and post-remission monitoring is essential 4.

The prognosis is generally favorable for Cushing's disease and benign adrenal causes when treated surgically, with most cutaneous manifestations (including striae color intensity) resolving within 1-2 years, though light-colored striae may persist 2, 3.