We don't know why some people become allergic to nickel when others don't. But, those with certain jobs are more likely to become sensitive to nickel – these include hairdressing, nursing, catering, cash handling, and those handling metals.

What things contain nickel?

Almost anything made from metal contains nickel, especially if it's silver coloured. Some every day items which contain nickel are: coins, jewellery, metal ornaments, scissors, pins, needles, thimble, press studs, zips, paperclips, metal wool scouring pads, cigarette lighters, filing cabinets, pens, metal typewriters, handles, taps, keys, keyrings, saucepans (stainless steel) kitchen utensils, cutlery. As you can see it's almost impossible to avoid nickel at home or work. But luckily, most nickel-sensitive people find a rash only comes up if they are in contact with nickel for a long time or when their skin is wet or sweaty.

What does nickel allergy look like?

Many people sometimes notice a red, itchy rash under a jean stud, zip or watch strap buckle which can be due to irritation and sweat. Often this rash, called "jewellery dermatitis", is the first sign of nickel allergy. Nickel allergy makes the skin red and itchy at first - later on tiny water blisters can appear, making the skin moist and oozy. The skin may then peel off. This rash can start in one place or in a number of places on the body at the same time. If the condition carries on for a long time the skin will dry out and become red, scaly and cracked. Any part of the body can develop an allergic rash to nickel – hands, wrists, ears, and stomach are most often affected. Normally the rash appears wherever nickel is in close contact with the skin. But it is possible for the rash to spread so that later on even areas which haven't come into contact with the metal become red and itchy, although the rash is usually worse where the skin is in contact with nickel.

If you handle anything made of nickel, then traces of metal may remain on the fingertips and cause a rash elsewhere, such as on the eyelids or neck, if these are touched later. Once you have developed an allergic rash due to nickel on a particular part of the body, it's possible for the rash to spring up again on that site whenever you come into contact with nickel, even at a different place on your body. So, you could touch nickel with your fingers, and get a rash on your ear lobes as well! Soon after becoming allergic to nickel, if you avoid any contact with it, the rash will clear and leave your skin looking just as before. But if the rash remains for a long time, because you didn't realise it was due to nickel, it can become very difficult to clear up, even when you no longer are in contact with the metal. If the hands become generally affected so that a rash covers them, this can be especially difficult to clear – this is a particular problem for those who do a lot of housework, and those whose jobs involve their hands being frequently wet. Once the hands have become affected it's really important to protect them until the skin is properly healed,otherwise they will remain sore for a long time. Most people realise they're allergic to nickel because of where the rash is, for example under earrings. But if your rash is in an unusual place or really bad, the cause may not be clear. In this case your GP might refer you to a dermatologist who may carry out patch tests to see if you're allergic to nickel.

Can an allergic rash become infected?

Yes – if the skin becomes moist then it can become infected with bacteria. The same is true if the skin becomes broken and raw, perhaps because of scratching – the hands are especially likely to become infected. If the skin becomes crusted and yellow, weeps, or smells odd, then it is probably infected, and you should see your doctor to get treatment – the rash will not improve until you do so.

Which parts of the body are most often affected?

Any part of the body can develop a rash if something made from nickel comes into close contact with the skin. Common places to be affected are given below.

• Scalp: hairgrips, metal hairbrush, curlers
• Face: curlers, hairpins, jewellery, coins
• Eyelids: some eyeshadow, metal on fingertips, make-up brushes, eyelash curlers
• Nose: spectacle frames
• Lips: pins held in mouth, metal lipstick cases, pens, pencil ends
• Ears: earrings, spectacle frames, pens
• Neck: necklaces, clasps, zips, perfume sprays
• Chest: brooches, medallions, chains
• Breasts: wire support in bras, necklaces
• Back: clip & strap adjusters on bras, zips
• Stomach: press studs (especially jeans), clothes fastenings
• Arms: bracelets
• Wrists: watches (back, strap buckle), bracelets, metal scent bottles
• Hands: coins, umbrellas, metal trim on handbags & purses, handles, pram frames, taps, cutlery
• Fingers: rings, thimbles, scissors, pins & needles, coins, pens, typewriter keys
• Thighs: coins in pockets, metal chairs, metal clasps on suspender belts
• Feet: shoe buckles, metal studs