Cobalt allergy
Contact allergy to cobalt, often alongside nickel.
About cobalt allergy
Cobalt is a metal that frequently causes allergic contact dermatitis, a delayed, T-cell mediated (type IV) reaction appearing roughly 12 to 72 hours after skin contact. It is found in metal alloys, costume jewellery, some tools, and also in blue pigments used in ceramics, glass and paints, as well as in cement and certain leather items. Cobalt allergy very often occurs alongside nickel allergy, because the two metals are commonly present together, though a person can be sensitised to either one on its own.
The reaction is an itchy, red rash, sometimes with small blisters or scaling, developing where metal touches the skin, such as under jewellery, watch straps, belt buckles and clothing fasteners. In occupational settings it more often affects the hands. With ongoing exposure the affected skin can become dry, thickened and persistent, and flares may settle slowly.
Diagnosis is confirmed by patch testing performed by a dermatologist; skin-prick tests are not used for metal contact allergy. Management is based on identifying and avoiding cobalt sources, choosing jewellery and fasteners made from safer materials, and using barrier protection at work. Emollients help maintain the skin barrier, and topical steroids may be advised for active patches. See your GP or a dermatologist if a metal-contact rash is recurrent, widespread or not improving with simple measures.
Common triggers
- Cobalt and products containing it
Symptoms
- Red, itchy rash (contact dermatitis)
- Dry, cracked or scaly skin
- Blistering or weeping in severe cases
- Burning or stinging where skin met the trigger
Avoidance & management
- Avoid skin contact with the trigger
- Wear gloves or use barrier creams
- Choose products labelled free from the allergen
- Rinse skin promptly after contact
- Use emollients or prescribed steroid creams
Sources & references
Allergy safety: what everyone should know
Mild-to-moderate reaction signs
- Itching, hives or a raised rash
- Swelling of lips, face or eyes
- Tingling mouth, sneezing, runny nose
- Stomach pain, nausea or vomiting
Anaphylaxis — call 999 (UK) or 112 (EU) immediately
- Difficult or noisy breathing, wheeze, persistent cough
- Swelling of the tongue or tightness in the throat
- Dizziness, collapse, pale and floppy (young children)
- Use an adrenaline auto-injector (e.g. EpiPen) at once if prescribed, then call an ambulance even if symptoms improve
Allergy or intolerance? A true allergy involves the immune system and can escalate quickly; an intolerance (e.g. lactose intolerance) is unpleasant but not life-threatening. The symptoms overlap, so self-diagnosis is unreliable.
Getting tested: home-testing kits based on IgG are not diagnostically valid. If you suspect an allergy, ask a GP for referral to an allergy clinic for skin-prick or specific-IgE testing and a supervised food challenge where appropriate.