Definition
An abnormal skin sensation — typically tingling, prickling, burning, or a 'pins and needles' feeling — occurring without an external physical cause. In the context of altitude-induced decompression sickness (DCS), paresthesia results from nitrogen bubbles forming in tissues or pressing on nerves as ambient pressure drops.
Plain English
An odd skin feeling — tingling, prickling, or pins-and-needles — that happens on its own, without anything actually touching the skin. At altitude, it can be an early warning sign of decompression sickness.
Context Anchor
Seen in altitude-induced decompression sickness discussions, especially in symptom lists for pilots operating at high altitude or after a rapid loss of cabin pressure.
Derivation
From Greek 'para-' meaning 'beside' or 'abnormal,' and 'aisthesis' meaning 'sensation.' Literally 'an abnormal sensation' — a feeling that shouldn't be there.
Why Pilots Care
Identifying paresthesia as a possible sign of decompression sickness allows a pilot to descend promptly and seek medical attention before symptoms worsen.
Analogy
It can feel like the pins-and-needles feeling you get when a foot falls asleep, except in flight it may be caused by altitude-related pressure effects rather than by sitting in one position.
Intuition Check
Do not assume paresthesia means pain. It often means an odd feeling such as tingling, numbness, or prickling, and it can still matter even if it does not hurt.
Example Sentence 1
After a rapid climb to FL250, the pilot reported paresthesia in his left arm and immediately began a descent while requesting priority handling.
Example Sentence 2
Paresthesia around the knees was the first indication that decompression sickness might be developing.