They can be hypoallergenic depending on the metal used; looks for "pure" metals like Sterling Silver, Platinum, Stainless Steel or 18K Gold as solid options. Look for earring mountings and backings that prevent friction and avoid triggering allergic reactions.

• Hypoallergenic properties depends on the metal used for posts and backs
• High-quality craftsmanship helps prevent friction and discomfort

Aim for "pure" metals such as .925 Sterling Silver or 18K Gold. Sterling Silver is 92.5% pure, with only a small amount of nickel alloy to strengthen the metal, making it durable enough to wear daily. 18K Gold is 75% pure gold, and is alloyed with zinc, nickel and palladium, and usually is pure enough for most wearers with sensitive ears ... in addition, 18K White Gold is rhodium plated - rhodium is another pure metal that coats and protects against allergic reactions.

• Sterling Silver is a pure metal that is the most popular choice for sensitive ears
• 18K Gold is also an excellent option, 75% pure that usually doesn't irritate skin allergies
• 18K White Gold is rhodium-plated; rhodium is another pure metal that brightens the white gold color, and coats the metal posts and backs protecting against allergic reactions

That depends on how sensitive your ears are to the alloys used to strengthen the metal. Some wearers cannot tolerate 14K Gold, but can handle 18K Gold. Some wearers can only tolerate "pure" metals like Sterling Silver or Platinum. 

• Sterling Silver is the most reliable hypoallergenic metal choice because it's 92.5% pure with minimal alloys
• 18K Gold is the next most popular; most wearers with metal allergies are still able to tolerate gold that is 75% pure 
  

Pearl studs will not cause an allergic reaction any more than any other mounting style for earrings, as long as the metals used are either Sterling Silver or 18K Gold. Pearl studs - especially in smaller to moderate pearl sizes - are some of the lighter earring styles you can wear with minimal weight placed upon the piercing hole. Try not to sleep in your earrings or expose your sensitive ears to very long periods of wearing earrings to avoid irritating your skin.

• Pearl studs place minimal weight on the ear, especially in the smaller to more moderate pearl sizes
• Smooth sterling silver posts help reduce friction
• Avoid sleeping in your pearl jewelry, and avoid prolonged wear times for maximum comfort

Any metal jewelry - finished or simply mountings - are stamped with their official alloy mix. This can be numbers like 14K, 18K, 22K, etc., or their percentages such as .925 for Sterling Silver, 750 stands for 18K Gold, and 585 for 14K Gold. These numbers represent the amount of pure metal is in the jewelry, and gives you a clue as to how much alloy is mixed in. Check for these stamps in your mountings - they may be on the post, or backings in a discrete location and very small. 

• Check for the 925 metal hallmark denoting Sterling Silver on your mountings
• For 18K Gold, look for the 750 metal hallmark, which designates your mountings are officially 18K. 
  
• Avoid earring styles with no metal hallmarks or are heavily alloyed