Introduction 

Erythema multiforme (EM) is a skin disorder characterised by an allergic reaction to medication or an infection. Approximately 20% of the cases reported are in children. They undergo skin changes, such as lesions or rashes, which appear on the arms and legs; however, they do not have a specific pattern of where they appear. This can alarm some parents who are unfamiliar with what to look out for.¹

In this article, we will explore what EM is and how it is presented in children and adolescents. Additionally, what causes the condition and when parents should seek medical help. 

What is Erythema Multiforme?

EM is known as a hypersensitivity reaction and is most common in children. This is when the immune system can’t tell the difference between a healthy and an unhealthy substance in the body, and then attacks the healthy substance by mistake. The condition causes red spots that tend to begin on the feet and hands. The spots then turn to raised patches, known as plaques, that look like targets as they have a red centre, a pale colour around it and a red ring around the edge. This gives them the name “target lesions”. Next, we will analyse the classification of severity in EM.²

Erythema Multiforme Minor

Erythema multiforme minor is described as a mild case of EM. The rash tends to appear within 3 days, and children might present symptoms such as fatigue, malaise (general feeling of discomfort), or upper respiratory tract infections.³

Erythema Multiforme Major

Erythema multiforme major is described as a severe case of EM. After the presentation of the lesions in large areas of the skin, children might present moderate fever, aches, coughs, sore throat, chest pain, vomiting and diarrhoea, which continues for up to 2 weeks.³

Causes and triggers in children

Viral infections 

Most cases of EM are caused by a viral infection, such as herpes simplex virus (HSV), also known as cold sores. HSV can remain inactive in the body, presenting symptoms only when reactivated due to stress, another illness, or certain environmental factors.¹

Bacterial infections

Different bacteria can also trigger EM. In children, Mycoplasma pneumoniae is a common cause of chest infections, which can cause EM.¹

Medications

Certain drugs can cause EM; these include anticonvulsants, as well as nonsteroidal anti-inflammatory drugs, used for muscle pain, such as ibuprofen or aspirin. In addition, it can be caused by antibiotics.¹ 

Vaccinations

Although children are more likely to develop EM due to viral causes, vaccinations, such as the oral polio vaccine and the tetanus/diphtheria vaccine, might be a cause of EM in infants.¹

How Erythema Multiforme appears in children

EM typically begins with pink or red patches. Over time, they then begin to form into round spots that give the appearance of targets, due to their red and pale rings. Sometimes, they may be painful, itchy, or swollen.^1,2

The rash usually appears on the:^1,2

• Arms
• Legs
• Hands
• Feet
• Face
• Neck
• Diaper area

However, if there are rashes or spots around the mouth and lip area, this may be an indicator of erythema multiforme major. This should be escalated to a GP or healthcare professional. In addition, depending on where the rashes are formed on the body, a child may experience other symptoms, such as pain when urinating or finding it painful to eat or drink. Usually, when the rashes subside, they will leave dark spots, which will eventually fade. They do not leave any scars.^2,4

Other symptoms may occur, such as:

• Headaches
• Fatigue
• Fever
• Joint pain
• Sore, red eyes

Symptoms can be expected to self-resolve in the time frame of up to 4 weeks; however, it can take up to 6 weeks if the disease is more severe. It is important to note that EM is not contagious, and the symptoms presented by the infected individual can’t spread from person to person.^1,2,4

When to seek medical help

Sometimes, as parents, it is hard to identify when it is appropriate to seek medical help for your child. It is important that if parents think their child may have EM, to get them checked by a doctor, as other rashes can look quite similar.⁵

 These are some warning signs that parents can look for:^1,2,5

• Spots in the mouth or on the lips
• Spots around the eyes or red eyes
• Spots or rashes on the anus or genitals
• Struggling with drinking fluids
• Struggling to urinate
• Having a high temperature or feeling pain even after taking painkillers
• Rashes appearing after a child started taking a new medicine
• Peeling skin

It is also important to highlight that if a child presents with tightness in the chest or throat, trouble breathing or talking, and/or swollen mouth, face, lips or tongue, it is a sign of a serious reaction and may need immediate hospital care.^1,2,5

Diagnosis and medical evaluation

EM is diagnosed based on a person’s medical history in combination with a physical examination. This means that doctors ask about the individual’s recent symptoms, as well as medication usage. As EM can be caused by infections, it is necessary to do a mouth swab or a blood test.^1,2

Although many cases do not require further investigations after this, sometimes, if the case is unclear, then a healthcare professional will proceed with a skin biopsy. This is where a small sample of skin, taken and used for testing to exclude other diagnoses.^1,5

The skin biopsies vary based on the shape, size, colour, distance between each lesion, and where the lesions appear on the body. Direct microscopic diagnostics, such as immunofluorescence, may be used to help differentiate between EM or autoimmune blistering disease, to prevent misdiagnosis.^1,5

Treatment and care at home 

When it comes to treating EM, healthcare professionals typically focus on the underlying causes of the condition. For example, if EM is caused by a medication that a child has been taking, it would be stopped right away. If EM is caused by an infection, the infection itself would be treated.¹

Mild cases

In most mild cases, EM can be treated within a few weeks with the use of emollients and topical corticosteroids. These can be prescribed to speed up recovery time and help manage symptoms, such as itchiness and burning.^2,5

Severe cases

In severe cases, children may need to be cared for in a hospital, as the skin may need regular dressings, adequate pain relief, and fluid and salt replacements. In addition, if the skin is damaged and infected, antibiotics may be prescribed.^2,5

Other treatment measures

• Use of eye drops to calm redness and itchiness
• Soft and liquid diets if lesions are located in or around the mouth
• Mouth opening exercises if there is scarring around the mouth 

What parents should remember

It is important to remember that most children with EM experience the mild form of the condition. This means the most treatments are fairly simple, combining prescribed creams and corticosteroids, which usually clear up the lesions in under 4 weeks. However, it is essential to spot the more severe symptoms as soon as possible. Early recognition and early intervention can help ensure that a child will get the right care quickly.^1,2,5

Summary

EM is described as a skin disorder that is caused by an allergic reaction to medicine or an infection. This condition mostly affects children. EM can cause changes in the skin, such as lesions or rashes, which show up on the arms and legs; they do not have a specific pattern of where they appear. In mild cases, EM is easily treatable. However, in severe cases, it is necessary to hospitalise children. Therefore, parents must look for medical advice from their healthcare team.