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.
Sleep disorders such as sleep apnea, narcolepsy, restless legs syndrome, and insomnia can cause problem sleepiness. Sleep apnea is a serious disorder in which a person's breathing is interrupted during sleep, causing the individual to awaken many times during the night and experience problem sleepiness during the day. People with narcolepsy have excessive sleepiness during the day, even after sleeping enough at night. They may fall asleep at inappropriate times and places. Restless legs syndrome (RLS) causes a person to experience unpleasant sensations in the legs, often described as creeping, crawling, pulling, or painful.