Papular urticaria is an allergic skin reaction usually caused by insect bites. It is more common in children than adults and often appears on uncovered areas like the face, forearms, and legs.

Papular urticaria is a common condition, especially in the summer months. The red bumps occur due to a hypersensitivity to bug bites. It usually occurs in children but can also affect adults traveling to new areas.

One unique characteristic of this skin disorder is that scratching an area affected by a bug bite can trigger the inflammation of old bites. As a result, it can appear as though there are more new bites than there really are.

Read more to learn about papular urticaria symptoms, treatment options, and when to contact a doctor.

The first symptoms of papular urticaria are usually itching and inflamed, raised bumps. The bumps may appear in a curved pattern or a line, particularly if the bites are from bed bugs or fleas.

Although they can occur anywhere on the body, the bumps typically appear on exposed areas, such as the legs, forearms, and face.

The bumps — also called hives — are usually very itchy. People often have the urge to scratch, but doing so can break the skin. This can cause infections and scarring.

Each bump usually remains on the skin for a few days up to several weeks. The bumps may disappear quickly, only to reappear elsewhere. Papular urticaria tends to recur, and a new bite can trigger an old reaction.

Although it can look similar, papular urticaria is different from scabies, a skin condition caused by burrowing mites. Scabies is a contagious condition that causes rashes, sores, and thick crusts that last weeks. Scabies bumps are usually smaller and flatter in appearance than those that result from papular urticaria.

Many insects in the United States can potentially cause a reaction, leading to papular urticaria. The most common causes are insects that live on cats and dogs, such as fleas and mites. Bed bugs are another common cause.

However, any biting insect can cause papular urticaria.

A 2017 study published in the World Allergy Organization Journal found that 20% of children studied had experienced papular urticaria. Fleabites caused the condition in around 50% of those children.

The study identified risk factors that made children more likely to get papular urticaria, including:

  • having household pets
  • using a mattress without springs
  • daily use of public transportation
  • living in a warm, tropical climate
  • living in a geographic area heavily infested with insects
  • having siblings with a history of atopic dermatitis
  • being under 7 years old
  • being affected by poverty

Papular urticaria in children

Although papular urticaria can affect anyone, it is more prevalent in children than adults. It commonly occurs in children who are 2–7 years old.

Because papular urticaria results from a hypersensitivity to bug bites, people become less likely to get it with time. As children become more and more desensitized to common bug bites, they will “outgrow” the condition. Children tend to get papular urticaria because they have never been exposed to a certain insect bite before and have not yet become desensitized to it.

The bumps will usually go away on their own, but over-the-counter (OTC) medications and creams can ease discomfort, reduce swelling, and prevent infection.

If a person is experiencing serious itching or pain, or the bumps do not resolve, they should contact a healthcare professional. A doctor can carry out tests to rule out other causes, such as scabies and dermatitis.

The bumps usually go away on their own. People can use OTC creams and medications to manage discomfort but may need a prescription for stronger steroid creams.

Treatments for papular urticaria include:

However, the best way to manage the condition is to take preventive measures. People should cover their skin when outside, wear insect repellent, and treat household pets for fleas.

If a person has papular urticaria, it is also important to get rid of any sources of infestation. They can do this by:

  • treating household pets with flea medication
  • wearing protective clothing
  • using insect repellent
  • treating pet bedding with flea spray
  • spraying an area with insecticide
  • treating carpets and upholstery with a pyrethroid spray, being sure to vacuum afterward
  • checking mattresses for signs of bed bugs

The main complication of papular urticaria is infection. Because the condition causes itchy bumps, people can feel a strong urge to scratch.

This can lead to infections through germs on the fingers and nails entering the skin. Skin infections can cause pain and inflammation, which can worsen the condition.

Papular urticaria is a preventable condition. The best way to avoid it is to cover the skin when outside, use insect-repellent spray, and keep the home free of bugs.

Over time, most children and adults will become desensitized to papular urticaria.

If a person does get papular urticaria, it usually resolves on its own.

Papular urticaria is a skin reaction to an insect bite. It can either be an allergy or hypersensitivity. Symptoms include small, raised bumps that are itchy and painful.

The condition usually resolves on its own, and people can manage it with OTC antihistamines and creams. People should avoid scratching the bumps, as this can lead to infection.