Differential Diagnosis: Sweating in a 47-Year-Old Woman

1. PHYSIOLOGICAL / HORMONAL (Most Common)

Perimenopause / Menopause (#1 diagnosis to consider)

• Declining estradiol levels cause vasomotor instability - hot flashes/flushes, night sweats, diaphoresis
• Associated: irritability, sleep disturbances, vaginal atrophy, irregular menstrual cycles
• FSH elevated (>25 IU/L), estradiol low
• Source: Goodman & Gilman's Pharmacological Basis of Therapeutics

Pregnancy

• Can cause generalized hyperhidrosis (rule out if menstrual irregularity present)

2. ENDOCRINE CAUSES

Hyperthyroidism / Thyrotoxicosis

• Classic triad: heat intolerance + sweating + weight loss despite good appetite
• Also: palpitations, nervousness, tremor, increased bowel frequency, tachycardia
• Presentation common in 4th-5th decade in women
• Check TSH (suppressed), free T4/T3
• Source: Kanski's Clinical Ophthalmology; Robbins & Kumar Basic Pathology; Current Surgical Therapy 14e

Pheochromocytoma (must not miss)

• Classic triad: paroxysmal hypertension + headache + sweating + palpitations
• Episodic/paroxysmal nature is a key clue
• Catecholamine excess from adrenal medullary tumor
• Diagnosis: 24-hour urine metanephrines, plasma metanephrines
• Source: Harrison's Principles of Internal Medicine 22E; Katzung's Basic & Clinical Pharmacology

Hypoglycemia

• Sweating is a classic adrenergic symptom of hypoglycemia
• Check fasting glucose, HbA1c; think of this in diabetics or insulinoma

Acromegaly

• Growth hormone excess causes sweating, coarsening of features, enlarged hands/feet
• Source: Andrews' Diseases of the Skin

Carcinoid Syndrome

• Classic: episodic flushing (typically dry, without sweating - distinguishes it from pheo), diarrhea, bronchoconstriction
• Serotonin-mediated; sweating more prominent in atypical carcinoids
• Diagnosis: urine 5-HIAA, serum chromogranin A
• Source: Goldman-Cecil Medicine; Yamada's Textbook of Gastroenterology

Diabetes Mellitus (autonomic neuropathy)

• Peripheral autonomic neuropathy causes compensatory truncal hyperhidrosis with lower-limb anhidrosis
• Also: gustatory sweating (facial sweating triggered by eating)
• Source: Dermatology 2-Volume Set 5e

3. MALIGNANCY ("B Symptoms")

Lymphoma (Hodgkin's and Non-Hodgkin's)

• Classic B symptoms: fever + drenching night sweats + unexplained weight loss (>10% body mass)
• Lymphadenopathy on examination
• Source: Goldman-Cecil Medicine; K.J. Lee's Essential Otolaryngology

Other malignancies

• Metastatic tumor deposits can produce cytokines - fever and subsequent sweating as fever breaks
• Source: Bradley and Daroff's Neurology in Clinical Practice

4. INFECTIOUS / INFLAMMATORY

Tuberculosis

• Classic cause of night sweats, fever, cough, weight loss (especially in endemic areas)

Brucellosis, HIV, Infective Endocarditis

• All may cause constitutional symptoms including profuse sweating

Chronic infections

• Any occult chronic infection (abscess, empyema) can present with recurrent sweating

5. NEUROLOGICAL / AUTONOMIC

Primary (Essential) Hyperhidrosis

• Affects palms, soles, axillae; bilateral and symmetric
• Often has positive family history (~25%)
• Worse with emotional/physical triggers; typically does NOT occur during sleep (unlike secondary causes)
• Source: Bradley and Daroff's Neurology in Clinical Practice; Fitzpatrick's Dermatology

Autonomic Dysreflexia / Dysautonomia

• Spinal cord disease, Parkinson's disease, multiple system atrophy

Parkinson's Disease

• Associated with hyperhidrosis due to sympathetic dysregulation

Complex Regional Pain Syndrome (CRPS)

• Localized sympathetic sudomotor hyperactivity in affected limb

6. DRUG-INDUCED

• SSRIs / TCAs (antidepressants) - very common cause of hyperhidrosis
• Opioids
• Anticholinesterases
• Tamoxifen / hormone modulators
• Salicylates (salicylism)
• Substance abuse / withdrawal (alcohol withdrawal = delirium tremens with severe diaphoresis)
• Source: Andrews' Diseases of the Skin

7. OTHER SYSTEMIC

Approach Summary / Red Flags to Investigate