It is a common experience to observe differing temperature readings between ears when using an ear thermometer. While this can sometimes be a cause for concern, there are often straightforward explanations for these discrepancies. Understanding the mechanics of ear thermometers and the various factors that influence ear temperature can help demystify this phenomenon.
Understanding Ear Thermometers
Ear thermometers, also known as tympanic thermometers, measure infrared energy radiated from the eardrum and surrounding ear canal, converting it into a temperature reading. The eardrum, or tympanic membrane, is a suitable site for temperature measurement because it shares a blood supply with the hypothalamus, the part of the brain that regulates body temperature. This close connection means the eardrum’s temperature can reflect the body’s core temperature. For an accurate reading, the thermometer’s sensor must be properly aimed at the eardrum, not just the ear canal walls.
Factors Contributing to Temperature Differences
Several factors can lead to variations in temperature readings between the two ears. Differences in the anatomical structure of each ear canal, such as its shape or size, can influence how effectively the thermometer captures infrared signals from the eardrum. The presence of earwax or other obstructions can also block the infrared signal, potentially leading to lower or inaccurate readings.
The way the thermometer is positioned or angled during measurement is another significant factor. Improper insertion or an incorrect aiming angle can cause the device to measure the temperature of the ear canal lining instead of the eardrum, leading to an inaccurate result. External factors can also influence localized ear temperature. For instance, lying on one side can temporarily increase blood flow and temperature in that ear due to insulation. Environmental factors like exposure to drafts or having one ear covered can also affect its temperature.
Localized physiological conditions can also cause a temperature difference. An ear infection, such as otitis media, or swimmer’s ear can cause inflammation and a higher temperature in the affected ear. Recent activities like chewing, talking, or crying can temporarily affect ear temperature due to increased blood flow or muscle activity around the ear.
Ensuring Accurate Ear Temperature Readings
To obtain reliable ear temperature readings, it is important to follow specific techniques. Always read the thermometer’s instructions carefully, as models can vary. Proper insertion technique is important; for adults and older children, gently pull the ear up and back, while for infants, pull the ear down and back to help straighten the ear canal. This helps ensure the thermometer’s probe is directed towards the eardrum.
Allow a short waiting period between consecutive readings. Ensure the ear canal is clear of excessive earwax or debris, as these can interfere with accuracy. For consistent tracking of temperature over time, using the same ear for measurements is generally recommended.
When to Consult a Healthcare Professional
While minor ear temperature differences are often benign, certain situations warrant medical attention. If a high fever is detected, typically 100.4°F (38°C) or higher, especially in infants under three months of age, it is important to consult a healthcare provider. Medical attention is also advised if a fever is accompanied by other concerning symptoms, such as a stiff neck, severe headache, difficulty breathing, a rash, lethargy, or persistent vomiting.
Pain or discharge from the ear, particularly with a fever, should prompt a medical evaluation, as these can be signs of an ear infection. If there is persistent or significant temperature difference between the ears without an obvious benign cause, or if you are generally concerned about your or your child’s health, seeking professional medical advice is always a prudent step.