Lead poisoning: symptoms, causes, testing and treatment

Lead poisoning can be hard to spot because mild cases may cause no obvious symptoms. UKHSA says the diagnosis requires a high index of suspicion for this reason, and that low levels may not cause obvious health effects.

In children, UKHSA says symptomatic lead poisoning is most likely to present with loss of appetite, tummy pain, constipation and headache. Weight loss or failure to thrive has also been reported, children may be irritable or have reduced concentration, and anaemia may develop in more severe cases.

For the public, UKHSA says exposure to high levels of lead over a short time can result in stomach upset, mood changes, poor attention span, headaches, and damage to the brain and kidneys in severe cases. Children exposed in their first few years may later have a lower IQ, behavioural problems or nerve damage.

• Loss of appetite and weight loss.

• Tummy pain, nausea, vomiting or constipation.

• Headache.

• Irritability, mood changes, poor attention span or reduced concentration.

• Anaemia (low haemoglobin) in more severe cases.

• At very high levels: unsteadiness, seizures and swelling of the brain (rare).

UKHSA says the most important aspect of treatment is removal from exposure. Finding the source can take detailed questioning and persistence, and the source may be at school or a relative's or other frequently visited home. UKHSA health protection teams work with local authorities to investigate and advise homeowners or landlords.

For children, UKHSA guidance says management of blood lead concentrations above 0.24 micromol/L (5 micrograms/dL) but below 2.4 micromol/L (50 micrograms/dL) normally involves only removal from exposure, although iron and calcium supplements may reduce both pica and the absorption of lead. The blood test is usually repeated about 4 weeks after exposure is removed.

Chelation therapy uses medicines to bind lead so it can be passed out of the body. UKHSA says it is reasonable to offer it to children who are symptomatic or have a level above 2.4 micromol/L (50 micrograms/dL), after expert advice from the National Poisons Information Service. It also notes that chelation is futile if re-exposure occurs afterwards.

Lead is a metal with a long history of use in paint, pipes, petrol and industry. UKHSA says there is no known safe level of lead exposure and that children's developing nervous systems are particularly susceptible, with effects reported at blood lead levels below 0.24 micromol/L (5 micrograms/dL).

In England, UKHSA becomes involved in finding and reducing the source at 0.24 micromol/L (5 micrograms/dL) or above in children under 16 and in pregnant women, and at 0.48 micromol/L (10 micrograms/dL) or above in other adults. UKHSA estimates around 6% of children have a level at or above 5 micrograms/dL.

Severe symptoms usually appear only at much higher levels. UKHSA, quoting the US agency ATSDR, lists anaemia, colic, nausea, vomiting, diarrhoea, headache and nerve damage above 1.45 micromol/L (30 micrograms/dL), and swelling of the brain and seizures above 4.83 micromol/L (100 micrograms/dL).

UKHSA says most exposure in the UK is from historic sources. Ingestion of lead-containing paint remains the most common source identified in children with raised levels, as lead was widely used in household paint until the mid-1960s, with some uses into the 1980s. Lead paint has not been used since 1992 according to the public guidance, but may remain beneath newer paint in older properties.

Renovation can create danger if sanding or heat-stripping old paint produces flakes, dust or fumes. UKHSA also lists sucking or chewing painted toys that do not meet safety standards, cooking with lead-glazed earthenware, traditional or natural remedies and supplements, spices and cosmetics, soil, and drinking water.

In adults, workplace exposure can occur in occupations such as steel welding and spray coating, roofing, battery manufacturing or plumbing. UKHSA says employers must comply with the Control of Lead at Work Regulations 2002, and that lead dust can be carried home on work clothing or through hobbies such as stained-glass making.

UKHSA says significant lead contamination of domestic water supplies is rare, but homes built before 1970 may have lead pipes. Since 1999 it has been illegal to use lead solder or brass fittings in water supplies, although lead can still be used in central heating systems.

If drinking water is suspected, your water supply company should test it. UKHSA says the prescribed limit is 10 micrograms per litre, and that running the main kitchen tap for generally 2 to 3 minutes to clear water that has stood in the pipes, for example overnight, can bring levels down. A qualified plumber, for example one accredited through WaterSafe, should do any pipework replacement.

Soil in gardens in former industrial areas, near busy roads or in areas mined for metal can contain lead. UKHSA says most toddlers will eat or pick at soil at some point, but that if a child has pica (recurrent eating of unusually large amounts of soil) it should be discussed with a GP.

UKHSA says babies and infants commonly put non-food items in their mouths as normal behaviour, but older children may develop pica, an eating pattern where they eat items such as hair, dirt and paint chips. Pica may co-occur with autism and other neurodevelopmental conditions.

If a child with pica picks at loose paint flakes or chews painted wooden items, UKHSA says they may need a blood test. Clinicians are advised to have a low threshold for testing children with learning disabilities or behavioural disorders because pica can be harder to identify.

In a UK surveillance study, children with pica or those who were crawling or of pre-school age accounted for most notified cases. UKHSA reports that 121 children in England were notified in 2021, rising to 191 in 2022.

UKHSA says lead crosses the placenta and can affect the developing baby, and that high exposure in pregnancy has been linked in some studies to miscarriage, impaired growth in the womb and premature labour. It recommends that pregnant women avoid activities with a risk of high lead exposure, and use protective equipment if they cannot, for example at work.

Traditional medicines and cosmetics where the ingredients are unknown, such as unbranded products bought online, are not recommended in pregnancy. If blood tests show high lead levels, UKHSA says additional monitoring of the baby's growth and repeat blood tests are likely to be offered.

UKHSA says a whole blood lead concentration should be done in all cases of suspected lead poisoning, and can be arranged and paid for by the GP or general hospital. A result requested from an NHS hospital should be available within a week. If exposure is at work, occupational health is responsible.

A doctor may also check a full blood count, iron status, and calcium, and may use an abdominal X-ray if a lead-containing object has been swallowed. UKHSA says testing hair, teeth or fingernails for lead is not recommended.

UKHSA says blood lead levels fall slowly in children. Levels may remain raised 6 to 12 months after exposure is reduced because additional sources have not been found, the measures have not worked, or lead stored in bone from past exposure has moved back into the blood.

For that reason a clinician may repeat the test after a longer interval, for example 6 months in some complex cases, and further follow-up depends on the child's condition, for example if pica continues.

UKHSA says that if you have health concerns about lead exposure you should seek guidance from your GP or contact NHS 111. Ask for a blood lead test if your child has persistent pica, lives in or is near renovation of an older home, or has unexplained tummy pain and constipation.

• Call 999 or go to A&E for a seizure, which UKHSA lists as a possible effect at very high lead levels.

• Contact your GP or NHS 111 if you or your child may have swallowed lead paint, a lead object or a remedy that may contain lead.

• Speak to your GP if you are pregnant and think you may have been exposed to lead.

• Contact occupational health or your GP if you work with lead and have symptoms.

On the NHS the route is your GP or a paediatrician, who can arrange a blood lead test and involve the local UKHSA health protection team and council environmental health service. Clinicians can get expert advice from the National Poisons Information Service, and the public should call NHS 111.

Private testing exists, but UKHSA advises that if parents provide a result from an external laboratory it is important to ensure the laboratory is appropriately accredited. Public health follow-up, such as sampling for the source, is arranged through UKHSA and the local authority.