Evaluation and Management of Sweaty Palms and Soles in an Infant Boy
The priority in an infant boy with excessive sweating of the palms and soles is to exclude cystic fibrosis (CF) through sweat chloride testing, as CF is a life-threatening condition that requires prompt diagnosis and treatment. 1
Initial Evaluation
Critical First Steps
- Obtain a detailed medical history focusing on red flag symptoms including persistent or recurrent cough, bulky and foul-smelling stools, poor weight gain or failure to thrive, frequent respiratory infections, and salty-tasting sweat on the skin 1
- Perform a thorough physical examination assessing growth parameters, respiratory status, and stool characteristics 1
- Evaluate environmental factors such as room temperature and overbundling, as overheating can cause sweating in infants 2
Laboratory Investigation
Order sweat chloride testing as the priority investigation when the infant weighs more than 2 kg and has a gestational age of at least 36 weeks 1. The test should be performed bilaterally to increase the likelihood of adequate collection 1.
Additional initial laboratory tests should include:
- Complete blood count 1
- Thyroid function tests (TSH, free T4) to exclude hyperthyroidism 1
- Blood glucose level 1
Interpretation of Sweat Chloride Results
Diagnostic Thresholds
- Sweat chloride ≥60 mmol/L confirms the diagnosis of CF 2, 1
- Values between 30-59 mmol/L are considered intermediate and require extended CFTR genetic testing 1
- Infants with CF often present with initial sweat chloride values in the intermediate range (30-59 mmol/L), which may increase over time 1
Follow-up Testing
- If the sweat chloride test is abnormal (≥30 mmol/L), repeat the test for confirmation and perform extended CFTR genetic testing 1
- A second elevated sweat test result is required to confirm the diagnosis 2
Management Based on Findings
If Cystic Fibrosis is Confirmed or Suspected
- Refer immediately to a specialized CF center for further evaluation and management 1
- Initiate selective respiratory cultures for Pseudomonas aeruginosa and Staphylococcus aureus 1
- If suspicion persists despite initial negative testing, retest at 6 months and annually until age 8 years 1
If Cystic Fibrosis is Excluded
After ruling out CF and other secondary causes (hyperthyroidism, hypoglycemia), consider primary focal hyperhidrosis, though this is uncommon in infancy:
- Primary hyperhidrosis typically presents as bilateral, symmetric, focal excessive sweating 3, 4
- The average age of onset is 14-25 years, making infant presentation unusual 5
- In infants, environmental management is the first-line approach: ensure appropriate room temperature, avoid overbundling, and dress the infant with no more than one layer more than an adult would wear 2
Important Clinical Pitfalls
Common Mistakes to Avoid
- Do not dismiss sweating as benign without excluding CF, as early diagnosis dramatically improves outcomes and prevents life-threatening complications 1
- Do not wait for the classic triad of symptoms before testing for CF; many infants present with isolated findings 1
- Avoid using keratolytic agents (urea, salicylic acid, lactic acid) on palms and soles in the neonatal period except in very limited circumstances, as these can cause systemic toxicity due to immature epidermal barrier and higher body-surface-to-mass ratio 2
- Parents should evaluate for signs of overheating such as sweating or the infant's chest feeling hot to the touch, as this may indicate environmental rather than pathologic causes 2
When to Escalate Care
Urgent referral is warranted if any of the following are present: