What Is Gianotti-Crosti Syndrome?

Medically Reviewed by Debra Jaliman, MD on May 20, 2024
4 min read

Gianotti-Crosti syndrome is a rash that usually affects young children. It's sometimes called papular acrodermatitis of childhood. The rash covers the arms, legs, and face. It can cause itching and discomfort.

Gianotti-Crosti is usually a delayed immune reaction to a virus. The rash will appear as your child is recovering from an illness such as a respiratory infection or stomach virus. It's very common and doesn't have lasting effects, but it can be alarming when it appears on your child's skin.

Viral illnesses trigger Gianotti-Crosti syndrome. The rash will typically begin as your child is recovering from another illness. Some children also get it after receiving live-virus vaccinations, such as the shots for poliovirus, hepatitis A, diphtheria, smallpox, pertussis, and influenza.

It's most common in children under the age of 9 years old, and children with underlying skin conditions like atopic dermatitis are also more likely to develop Gianotti-Crosti. Adults can get it, too, with women being more susceptible to it than men. The condition is most prevalent in spring and summer.

Doctors aren't sure why some viruses lead to a Gianotti-Crosti response. There is a broad assumption that it's part of the immune response to viruses, but experts don't know exactly why some people get it while others don't‌. 

The most common triggers for Gianotti-Crosti in the United States include:

In regions other than the United States, hepatitis B is a common trigger for Gianotti-Crosti syndrome. In the United States, children are usually vaccinated against hepatitis B. If your child has not been vaccinated for hepatitis B, you may need to have them tested if symptoms manifest.

A Gianotti-Costi rash looks like an outbreak of raised blisters that appear on your child's skin. The rash often first appears on or near the buttocks, then spreads to the arms, legs, and face. The blisters vary in size and may be filled with fluid. They may be pink, red, or brown in color.

The blisters may become itchy or uncomfortable. Your child may also have swollen lymph nodes and a mild fever along with the rash. Children may also experience swelling of the liver or spleen, but you would need a doctor to confirm those symptoms. 

The rash usually lasts about four weeks, though it can linger as long as eight weeks. It will go away on its own. The rash doesn't typically cause scarring on the skin. There may be dark spots that remain on the skin, but they generally fade after six months. Any other symptoms will also clear up over time. 

Tests are not needed to diagnose Gianotti-Crosti syndrome. Your child's doctor will do a physical exam and ask questions about how long the rash has been present.

Your doctor will also ask about any illnesses your child may have had in the weeks before the rash appeared. They might check their vaccination records to see if a recent inoculation could be the cause of the rash. If there is cause to worry about a serious viral infection such as hepatitis or HIV, they may test for that. 

The main symptom -- the rash -- will go away on its own. But if it’s itchy, you can use over-the-counter anti-itch treatments to ease the symptoms. Your doctor may suggest oral antihistamines if topical treatments don't help. Cool compresses may also reduce itching.

If your child has a fever, ask your doctor about using a fever reducer such as acetaminophen or ibuprofen. Ask about appropriate dosing for your child's age. Make sure your child drinks plenty of fluids, since fevers can be dehydrating. 

Gianotti-Crosti syndrome is not contagious, so you don't need to isolate your child while they have the rash. In fact, the rash usually appears after the child has stopped being contagious with the virus that triggered the syndrome. Your child can participate in activities while the rash is still present, though you may need a note from your doctor to explain the situation.