What is temperature sensitivity?

Temperature Sensitivity: Definition and Clinical Implications

Temperature sensitivity refers to an abnormal physiological response to changes in environmental or body temperature, characterized by exacerbation of symptoms or discomfort when exposed to heat or cold.

Types of Temperature Sensitivity

Temperature sensitivity can manifest in different ways:

• Heat Sensitivity: Worsening of symptoms or discomfort when exposed to high temperatures
• Cold Sensitivity: Worsening of symptoms or discomfort when exposed to low temperatures
• Dual Sensitivity: Some individuals experience sensitivity to both heat and cold

Physiological Basis of Temperature Sensitivity

Temperature sensitivity involves several physiological mechanisms:

1. Vascular Response:

   • Cold exposure causes initial vasoconstriction followed by vasodilation when returning to normal temperature
   • This rapid change can cause postural hypotension leading to dizziness 1

2. Neurological Impact:

   • Temperature changes can affect neural conduction, especially in demyelinated nerves
   • In conditions like multiple sclerosis, temperature changes can temporarily block or slow neural conduction 2

3. Age-Related Changes:

   • Thermal sensitivity varies approximately 100-fold over the body surface
   • The face, especially near the mouth, is most sensitive to temperature changes
   • All body regions are more sensitive to cold than to warmth
   • Thermal sensitivity declines with age, with greatest changes in the extremities 3

Clinical Manifestations of Temperature Sensitivity

Heat-Related Manifestations

Heat sensitivity can manifest as:

1. Heat Exhaustion:

   • Core temperature up to 104°F (40°C)
   • Normal mental status
   • Symptoms: weakness, dizziness, nausea, syncope, headache, fatigue, heavy sweating 1

2. Heat Stroke:

   • Core temperature ≥104°F (≥40°C)
   • Central nervous system dysfunction (confusion, delirium, seizures, coma)
   • Potential organ damage and circulatory failure 1

Cold-Related Manifestations

Cold sensitivity can cause:

1. Vestibular Disturbances:

   • Cold water in the ear canal can stimulate the vestibular system
   • May trigger Benign Paroxysmal Positional Vertigo (BPPV)
   • Can exacerbate vertebrobasilar insufficiency 1

2. Vascular Response:

   • Initial vasoconstriction
   • Central blood volume shift
   • Post-immersion vasodilation
   • Blood pressure fluctuations leading to dizziness 1

Temperature Sensitivity in Specific Conditions

Multiple Sclerosis (MS)

• Affects 60-80% of MS patients 2
• Symptoms temporarily worsen with environmental or exercise-induced temperature changes
• Both increases and decreases in body temperature can trigger symptoms
• Primarily driven by temperature-dependent slowing or blocking of neural conduction
• Affects both sensory and cognitive function 2, 4
• Distribution of symptoms:
  • 58% heat sensitive only
  • 29% both heat and cold sensitive
  • 13% cold sensitive only 4

Respiratory Viral Infections

• Many respiratory viruses show temperature sensitivity
• These viruses replicate poorly at normal body temperature (restrictive temperature)
• They replicate well at lower temperatures found in the upper airway (permissive temperature)
• This temperature sensitivity helps viruses:
  • Restrict infection to upper airways
  • Cause mild illness with limited immune response
  • Trigger symptoms like rhinorrhea, coughing, and sneezing that aid viral spread 5

Management of Temperature Sensitivity

Heat-Related Conditions

1. Heat Exhaustion:

   • Move to a cool place
   • Remove excess clothing
   • Lie down
   • Apply cool water spray to skin
   • Drink cool fluids with electrolytes and carbohydrates 1

2. Heat Stroke (Medical Emergency):

   • Activate emergency medical services immediately
   • Begin rapid cooling without delay using cold/ice-water immersion or ice packs
   • Continue cooling until core temperature reaches just under 39°C (102°F) or neurological symptoms improve
   • The speed of cooling directly correlates with survival 1

Cold-Related Symptoms

For dizziness after cold exposure:

• Sit or lie down immediately
• Hydrate adequately
• Move to a neutral temperature environment
• Apply counter-pressure 1

Prevention Strategies

1. For Heat Sensitivity:

   • Acclimatization to heat
   • Adequate hydration before, during, and after exercise
   • Avoid strenuous activity during extreme heat
   • Wear loose-fitting, light-colored clothing
   • Take regular breaks in cool environments 1

2. For Cold Sensitivity:

   • Gradual acclimatization
   • Proper hydration
   • Controlled breathing
   • Gradual temperature transition
   • Avoid standing immediately after cold exposure 1

When to Seek Medical Attention

Seek immediate medical attention if:

• Dizziness persists for more than 15 minutes after temperature exposure
• Severe headache, confusion, or loss of consciousness occurs
• Neurological symptoms develop
• Core temperature reaches or exceeds 104°F (40°C)
• Mental status changes occur after heat exposure 1

High-Risk Populations

• Children and adolescents
• Elderly individuals
• Obese individuals
• People with chronic diseases
• Individuals taking certain medications (diuretics, antihypertensives)
• People with pre-existing cardiovascular conditions
• Individuals with multiple sclerosis or other neurological conditions 6, 1, 2