Health warning over Oak Processionary Moth Caterpillar

We are aware of an increasing problem in the local area from oak processionary moth catrerpillars. These caterpillars are covered in tiny hairs that can cause severe asthma attacks and allergic reactions. Until recently, the moth was found only in mainland Europe, but in 2006 it was discovered on oak trees in Ealing and Richmond, in London. The caterpillars feed on oak leaves and produce silken nests on the trunks of affected trees. There is no natural predator. The hairs can cause symptoms if the caterpillars or their nests are touched, but they can also be carried on the wind. The most common symptoms are an unpleasant rash. Less common problems are sore throats, breathing difficulties or eye problems. Asthma UK has advised those with asthma always to remember to carry a reliever inhaler with them in case of an unexpected attack.

The caterpillars or their nests should not be touched. You should not attempt to remove them, but should report them to one of the addresses given below.

Who is affected by these caterpillars? The caterpillars’ hairs can affect anyone, but asthmatics in particular are at risk of having a severe attack. The hairs can also affect animals, including dogs, cats and horses, so people are also encouraged to keep their pets and livestock away from infested trees.

Why do these moths cause health problems? Health problems are most common when the caterpillar is in its last stages of development in late May and early June, before becoming a moth. This is because the caterpillars are covered with tiny hairs that contain a toxin (thaumetopoein or closely related compounds). If these hairs and toxins come into contact with the skin they can cause symptoms.

What sort of symptoms do they cause? If the hairs or toxins come into contact with the skin they can cause a very itchy skin rash. If they come into contact with the eyes they can cause itchy eyes. Can the symptoms be serious? People vary in their response - not everyone reacts to the caterpillar hairs. The most common problem is an itchy rash which is unpleasant but not dangerous.

What should I do if I develop these symptoms? The recommended treatment includes an oral antihistamine, such as cetirizine or loratadine. Speak to your chemist for advice. If the itching keeps you awake, a sedating antihistamine such as chlorphenamine (Piriton®) may help in addition. Topical steroid cream such as hydrocortisone can also be purchased from the chemist and this may soothe the rash further.  If your symptoms are not responding to this, ask for a telephone consultation with your GP. If you have any breathing difficulty, consider booking an appointment or A&E in extreme cases.

What should I do if I see a nest? Anyone who thinks they have found oak processionary caterpillars or their nests should not touch them or attempt to remove them, but should report their sightings to the Forestry Commission with its Tree Alert on-line pest reporting tool, giving as precise details as possible about the location.

Private Prescriptions 
Please be advised that prescriptions issued by a Private Consultant cannot be converted into NHS Prescriptions. You need to take your Private Presciption to a Chemist who will advise you of the charge. Even if this is high, we are not allowed by new NHS rules to issue them.