Photo Credit pollen image by asb from Fotolia.com. Allergies are a common cause of hives since an allergic reaction can trigger the immune system response that results in trapped fluid beneath the skin. An allergic reaction can occur due to something you ingested or were exposed to through the air.hoto Credit pollen image by asb from Fotolia.com. Allergies are a common cause of hives since an allergic reaction can trigger the immune system response that results in trapped fluid beneath the skin. An allergic reaction can occur due to something you ingested or were exposed to through the air.
There are likely to be other possible causes, so ask your doctor about your symptoms. 1  Various causes of drowsiness or sleepiness include: 2  Sleep debt. 3  Not getting enough sleep. 4  Shift work. 5  Jet lag. 6  Boredom. 7  Fatigue-see various causes of fatigue. 8  Sleepiness-see various causes of sleepiness.
How they can cause insomnia: Alpha-blockers are linked to decreased REM (rapid eye movement) sleep â the stage of sleep when people dream â and daytime sedation or sleepiness. The proportion of REM sleep drops markedly in old age, and people deprived of REM sleep can experience memory problems.