Brittle asthma is a rare form of severe asthma. The term “brittle” means difficult to control. Brittle asthma is also called unstable or unpredictable asthma because it can suddenly develop into a life-threatening attack.
Unlike less severe types of asthma, brittle asthma tends to be resistant to the usual treatments, such as inhaled corticosteroids. It can be life-threatening, and it involves more doctor visits, hospitalization, and medication than other types of asthma.
Brittle asthma affects about 0.05 percent of people who have asthma. Not all doctors agree with the use of this categorization, as some people with asthma who have their symptoms under control can still experience life-threating asthma attacks.
There are two types of brittle asthma. Both are severe, but they have very different patterns of severity.
This type of brittle asthma involves daily periods of breathlessness and frequent sudden attacks that are more acute. Breathlessness is measured in terms of peak expiratory flow (PEF). To be diagnosed with this condition, you’ll need to have wide daily variations in breathing more than 50 percent of the time over a period of five months.
People with type 1 also tend to have impaired immune systems and may be more susceptible to respiratory infections. More than 50 percent of people with type 1 brittle asthma also have food allergies to wheat and dairy products. You may also require frequent hospital admissions to stabilize your symptoms.
Unlike type 1 brittle asthma, this type of asthma can be well controlled by drugs for extended periods of time. However, when an acute asthma attack occurs, it will come on suddenly, usually within three hours. You may not be able to identify any recognizable triggers.
This type of asthma attack requires immediate emergency care, often including ventilator support. It can be life-threatening if not treated promptly.
The causes of severe asthma are not known, but some risk factors have been identified. Many of the risk factors for brittle asthma are the same as those for less severe types of asthma. These include the state of your lung function, how long you’ve had asthma, and the severity of your allergies.
Being a woman between the ages of 15 and 55 increases your risk for type 1 brittle asthma. Type 2 brittle asthma is seen equally in men and women.
Additional risk factors for brittle asthma include:
- being obese, which is often accompanied by sleep apnea
- specific gene mutations, including genetically determined resistance to certain asthma drugs
- environmental exposure to allergens, such as dust mites, cockroaches, mold, cat dander, and horses
- food allergies, including allergies to dairy products, wheat, fish, citrus, egg, potato, soy, peanuts, yeast, and chocolate
- cigarette smoking
- respiratory infections, especially in children
- sinusitis, which affects 80 percent of people with severe asthma
- pathogens such as mycoplasma and chlamydia
- impaired immune system
- structural changes in airways
- psychosocial factors, including depression
Age can also be a risk factor. In one study of 80 people with severe asthma, which includes brittle asthma, researchers found that:
- nearly two-thirds of participants developed asthma before age 12
- one-third developed asthma after age 12
- 98 percent of early-onset participants had positive allergy reactions
- only 76 percent of late-onset participants had positive allergy reactions
- people with early-onset asthma more commonly had a family history of eczema and asthma
- African-Americans are at increased risk for early asthma
Exactly how these factors contribute to brittle asthma is the subject of ongoing research studies.
To be diagnosed with brittle asthma, your doctor will physically examine you, measure your lung function and PEF, and ask about symptoms and family history. They must also rule out other diseases that can impair your lung function, such as cystic fibrosis.
The severity of your symptoms and your response to treatment will play a major role in diagnosis.
Managing brittle asthma is complex and requires an individual approach for each person. Your doctor will also discuss the serious complications that can arise from this condition. They may advise you to meet with an asthma counselor or group to better understand the disease and treatment.
Your doctor will treat and monitor any accompanying diseases you may have, such as gastroesophageal reflux (GERD), obesity, or obstructive sleep apnea. They’ll also monitor interactions between drug treatments for these diseases and your asthma.
Treatment for brittle asthma may include a combination of drugs, such as:
There are no long-term studies of combined drug therapies, so your doctor will closely monitor your response. If your asthma is under control with the combination therapy for three months, your doctor may adjust your drugs to the lowest effective doses.
Some people with brittle asthma are resistant to inhaled corticosteroids. Your doctor may try a higher dose of inhaled corticosteroids or prescribe their use twice a day. Your doctor may also try oral corticosteroids, but these have side effects, such as osteoporosis, and need to be monitored.
Your doctor may also recommend the following therapies in addition to steroids:
- Macrolide antibiotics. Results from one research study indicate that clarithromycin (Biaxin) may lessen inflammation, but further research is needed.
- Anti-fungal therapy. One study shows that oral itraconazole (Sporanox), taken twice a day for eight weeks, improves symptoms.
- Recombinant monoclonal anti-immunoglobulin E antibody. Omalizumab (Xolair), given monthly under the skin, has a positive effect on severity of symptoms and quality of life. This medication is expensive and may cause side effects.
- Terbutaline (Brethine). This beta agonist, given continuously under the skin or inhaled, has been shown to improve lung function in some clinical studies.
Nonstandard drug treatments
Other types of treatment may be beneficial in reducing the severity of symptoms in some people who don’t respond well to standard therapies. These are therapies undergoing clinical trials:
- One dose of intramuscular triamcinolone. In clinical trials, this treatment was seen to reduce inflammation in adults and also the number of asthma crises in children.
- Anti-inflammatory therapies, such as tumor necrosis factor-alpha inhibitors. For some people, these drugs have proved beneficial for the immune system.
- Immunosuppressive agents such as cyclosporin A. Some studies showed them to have beneficial effects.
- Other therapies that modulate the immune system, such as deoxyribonucleic acid (DNA) vaccines, are in early clinical studies and show promise as future therapies.
The key to managing brittle asthma successfully is to know the signs of an acute attack and be aware of your triggers. Getting emergency help promptly can save your life.
If you have type 2, it’s important to use your EpiPen at the first sign of distress.
There are some things you can do to help reduce your risk for an asthma attack:
- Minimize house dust by cleaning regularly, and wear a mask to protect yourself from dust as you clean.
- Use an air conditioner or try to keep the windows closed during pollen season.
- Keep the humidity level optimal. A humidifier may help if you live in a dry climate.
- Use dust-proof covers on your pillows and mattresses to minimize dust mites in the bedroom.
- Eliminate carpeting where possible, and vacuum or wash curtains and shades.
- Control mold in the kitchen and bathroom, and clear your yard of leaves and wood that can grow mold.
- Avoid pet dander. Sometimes an air-cleaner can help. Bathing your furry pet regularly will also help keep dander down.
- Protect your mouth and nose when you’re outdoors in the cold.