HLH (immune system overreaction)

Overview

HLH can be inherited in babies or triggered in adults by infections, cancers, or autoimmune disease.

The immune system becomes overactive and damages organs.

Symptoms

Common signs:

• High fever that won't go away
• Very sick

Less common

• Rash
• Yellow skin
• Enlarged liver or spleen
• Swollen glands

Look up a symptom: Fever

When to get medical care

Causes

Immune overreaction.

Does it spread or run in families?

• It isn't contagious. You can't catch it from someone else.

Who is more likely to get it

• Babies and young children: Inherited types
• People with Epstein-Barr virus, lupus, or lymphoma: Higher risk

Possible complications

• Organ failure: Liver, kidney, or lung failure

Diagnosis

This is diagnosed in the emergency room or hospital.

The exam

A physical exam.

Tests

Tests, if needed:

• Blood tests:

Treatment

Emergency care is needed. While waiting for help:

Self-care

• Emergency care
• Follow the hospital care plan

Which doctor treats this

• Emergency doctors treat it first, in the ER.
• They may send you to a hematologist (blood doctor).

Living with it

Support groups and helplines

• Genetic and Rare Diseases Information Center (GARD): Free NIH information on rare diseases, including where to find experts and patient groups.
• National Organization for Rare Disorders (NORD): Patient groups, help finding care, and aid programs for rare diseases.

Back to school, work, or sports

• Recovery time varies. Ask your care team when you can drive, lift, work, and exercise.

Children, pregnancy, and older adults

• Babies: Inherited types often appear early.

Pregnancy and breastfeeding

• If you're pregnant or planning to be, tell your prenatal provider about this condition.
• Don't start or stop any medicine on your own. Some are safe in pregnancy and some need to be changed.
• Ask before taking any pain reliever. The FDA advises avoiding ibuprofen and naproxen after 20 weeks unless your doctor says to.
• Breastfeeding: Most medicines are fine, but ask. The NIH LactMed database lists what's known about each one.

For caregivers

• Go to visits when you can and take notes.
• Keep a list of medicines, allergies, and doctors in one place.
• Learn the warning signs that need fast care.
• Learn CPR. Many hospitals and the Red Cross offer classes.
• Take breaks and ask for help. Caregivers need care too.

Outlook

Fast treatment improves survival.

Getting ready for your visit

Bring a list of your symptoms and medicines.

What to bring

• A list of your medicines and supplements
• Notes on when symptoms started and what makes them better or worse

Questions to ask

• What follow-up care do I need?
• How can I prevent this from happening again?

Research studies

Research studies test new ways to find and treat health problems. Some are looking for volunteers. Talk with your doctor before joining one.

Search ClinicalTrials.gov for studies on HLH (immune system overreaction)