Mold Allergy: Symptoms, Development, Treatment

Brief overview

  • Symptoms: Mold allergy can cause many symptoms, usually affecting the respiratory tract, skin or digestive tract.
  • Causes: Mold allergy is caused by sensitization to different components of the fungus; intensive contact (increased exposure) favors the development of an allergy.
  • Prevention: To minimize contact with mold, provide good air circulation indoors; avoid food with traces of mold, gardening, leaves and compost.
  • Treatment: The doctor usually treats an acute mold allergy with anti-allergic drugs; hyposensitization is possible for longer-term therapy.
  • Diagnosis: The physician determines an allergy to molds by analyzing the symptoms and confirming with a skin, blood or provocation test.
  • When to see a doctor: A doctor should always be consulted if a mold allergy is suspected, and immediately if symptoms are severe.

What are the symptoms of a mold allergy?

The symptoms of a mold allergy are varied. On the one hand, this is due to the fact that there are about one million different types of mold, on the other hand, the reactions turn out very differently. Allergic reactions or poisoning (toxic reaction) are triggered by different parts of the fungus. Some people react only to the fungal spores, others also to the fungal threads (mycelium).

The most common symptoms of mold allergy are:

  • Irritation of the mucous membranes (MMI, Mucous Membrane Irritation).
  • Cough, rhinitis, sneezing, stuffy nose
  • Chronic sinusitis
  • Allergic bronchial asthma
  • Allergic conjunctivitis (rhinoconjunctivitis)
  • Itchy, red and watery eyes
  • Neurodermatitis (atopic eczema)
  • Hives (Urticaria)

Roughly, a distinction is made between symptoms triggered by external contact (e.g. via mucous membranes and respiratory tract) with parts of molds and those that enter the body via food. In the case of contact via the mucous membranes of the respiratory tract, the consequences include watery eyes, runny nose and swollen airways. When the fungi enter the body through food, they often trigger symptoms in the gastrointestinal tract (nausea, malaise, diarrhea) or skin reactions such as hives.

In the case of a mold allergy, immediate reactions (allergy type 1), but also time-delayed, severe illnesses are possible (allergy types 3 and 4, allergy late type). Learn more about the different allergy types here.

Can a mold allergy lead to a cross-reaction?

A cross allergy to molds is usually directed to other forms of molds. This means that if there is a mold allergy to a certain type of fungus, those affected usually also react to similar types of mold. It is therefore often not possible to clearly identify which is the original allergy and which is a cross-reaction. This plays a role, for example, in specialized immunotherapy (hyposensitization), for which the physician must know the initial cause of the allergy.

Some groups of antibiotics such as penicillin or ampicillin and amoxicillin were biochemically developed on molds and may cause allergic reactions in mold allergic patients. Be sure to inform your doctor about your allergy before taking these medications!

How does a mold allergy develop?

After repeated contact with the substance classified as dangerous, the sudden defense is switched on, triggering an allergic reaction. What the reactions look like in detail depends on the type of allergy.

In the immediate type, the immune system forms specific antibodies (immunoglobulins, IgE) against the mold, which are activated on contact with it and lead to symptoms within a few minutes. In allergy type 4, on the other hand, the immune cells play an important role. The defense cells (T cells) are activated by the mold and often lead to particularly strong reactions.

A weakened immune system, a difficult-to-treat cold (rhinitis) or sinusitis promote the development of an allergy. Difficult-to-treat asthma, a hereditary hypersensitivity (atopic predisposition), and a history of allergies also increase the risk of mold allergy.

  • Waste management (waste disposal, separation, incineration, sorting of recyclables and composting)
  • Agriculture (hay, animal husbandry)
  • Feed production
  • Plant processing (horticulture, woodworking and floriculture)
  • Viticulture and brewery
  • Flour processing (miller, baker, confectioner)
  • Ventilation and air conditioning

What should not be eaten if you are allergic to mold?

To avoid allergic reactions, it is important for sufferers not to eat foods affected by mold. Visible mold indicates that food is spoiled and no longer edible. Even if there is no allergy to mold, it is harmful to health. Foods particularly susceptible to mold infestation are:

  • Fermented beverages (beer, wine, kefir)
  • Fruit juices
  • Molded cheese (blue cheese such as Brie, Camembert, Roquefort) and salami
  • Bread (especially rye bread)
  • Cereals

How is a mold allergy treated?

In order to be able to treat a mold allergy, it is first necessary to find its sources. In addition to medical examinations, it is worth taking a look at the allergy sufferer’s home and workplace. Because also the avoidance of molds is an important measure of the therapy. For a permanent improvement of the complaints, in some cases a change of the living or occupational situation is helpful or necessary (move, renovation of the living space, change of job).

For the treatment of a mold allergy, the doctor usually prescribes anti-allergic drugs for acute relief of symptoms. They are available in the form of tablets, sprays or drops. Active substances to combat fungi (antimycotics) in the form of an ointment or tablets are often also part of the treatment. Hyposensitization is also possible for the longer-term therapy of a type 1 mold allergy.

For hyposensitization, the allergen that triggers the allergy must be identified and artificially produced. Currently, hyposensitization is possible for 30 to 40 mold allergens. The active ingredient for the therapy can be injected under the skin (SCIT, subcutaneous immunotherapy) or taken under the tongue via a tablet or drops (SLIT).

How can molds be avoided?

There are a few ways to avoid mold in your home. Molds, like all types of fungi, spread best in a humid and warm climate. Therefore, it is important to keep the humidity in living spaces as low as possible. Areas particularly at risk for mold infestation are:

  • wood (e.g. the back walls of closets)
  • Wallpaper
  • Cardboard (carton)
  • Carpeting

What can you do to prevent mold in the apartment?

  • Ventilate regularly! Ventilating at least three times a day for five to 15 minutes is ideal.
  • Bathrooms and kitchens often accumulate a lot of moisture due to showering and cooking. Ensure sufficient air circulation!
  • Keep shower cabin and tub dry after use.
  • Provide sufficient heating! This prevents the damp cold air from condensing on windows or settling on other surfaces of the home.
  • Do not place furniture directly against exterior walls to allow air circulation.
  • Avoid humidifiers or air conditioners altogether, if possible, or provide regular maintenance.
  • Indoor plants also increase humidity and exacerbate allergy symptoms. It is recommended that you avoid them, especially in the bedroom.
  • Empty all trash cans regularly.
  • Dust frequently (especially during pollen season).
  • Studies show that by renovating the apartment, the moisture and thus the spread of mold is contained. This has a positive effect on various allergies affecting the respiratory tract and asthma.

Molds are always harmful to health. Regardless of whether they are still actively growing or have already dried out.

What should mold allergy sufferers be aware of outside?

Avoiding contact with mold outdoors is difficult. However, these tips are helpful in keeping exposure to allergy sufferers to a minimum.

  • Avoid gardening and being near compost, wet leaves or lawn clippings.
  • The calendar also plays a role in mold allergies: avoid spending extended time outdoors in wet weather in late summer and fall.
  • Avoid walks in the woods after rainy weather.

How does mold spread?

Some types of mold are found mostly indoors, while others are found mostly outdoors. Medical experts suspect that the greater part of all mold allergies is triggered by fungal species that occur outdoors.

In late summer to early fall, the highest levels of mold are measured in fresh air. This is due to the alternation of heat and rain or high humidity during this time of year.

How do you recognize a mold allergy?

Due to the many possible symptoms in a mold allergy, it is often difficult for the attending physician to diagnose it clearly. During the consultation (anamnesis), the doctor tries to find out more about the cause of the mold allergy and to exclude other triggers of the symptoms. In doing so, he asks some questions, for example:

  • When did the symptoms start?
  • Do the symptoms change in different places?
  • Do the symptoms occur all year round or do they depend on the season?
  • Do you have pets and if so, do symptoms worsen after contact with them?

During the physical examination, the doctor focuses on the mucous membranes of the respiratory tract, eyes and the skin of the affected person.

Different tests help the doctor to recognize a mold allergy and to differentiate it from other allergies. To distinguish whether it is a mold allergy or a dust mite, grass and herb pollen allergy, the doctor often resorts to skin, blood or provocation tests for diagnosis.

If symptoms worsen in rain and strong winds, this is often an indication that it is a mold allergy and not a pollen allergy.

Skin test

The symptoms usually peak after 15 to 20 minutes and usually subside again after two hours. This is what doctors call an immediate type reaction. This can also occur with a slight delay. A late type reaction is when the symptoms appear hours to days after the test.

So far, there are solutions for 30 to 40 different types of mold for an allergy test on the skin. If the allergy exists to another type of fungus, it cannot be detected by a skin test.

Taking medication (antihistamines or cortisone-containing agents) can falsify the result.

Blood tests

Provocation tests

Provocation tests are used when blood and skin tests have not provided clear results. These tests are performed on the eyes, bronchial tubes or nose. The physician specifically exposes the selected body site to a mold solution and observes the reaction to it. With this type of test, it is necessary for the affected person to continue to be under medical care for at least half an hour after the test in order to monitor any delayed reactions as well.

Provocation tests are not performed if:

  • The nose is acutely inflamed
  • There are currently severe symptoms
  • Acute allergic diseases of other organs are present
  • The patient is younger than five years old, because they can trigger strong, in the worst case life-threatening allergy attacks
  • Certain medications are being taken (beta blockers, ACE inhibitors)
  • The person has had severe allergic reactions in the past (anaphylactic shock)

What is a mold allergy?

In the case of a mold allergy, those affected react with different symptoms to contact with components (fungal spores or filaments) of molds. As with any allergy, this results in an overreaction of the immune system to a substance that is harmless in itself. The symptoms are very varied, but irritation of the mucous membranes and eyes is particularly common.

If the mold is ingested through food, nausea, vomiting, diarrhea or skin reactions such as hives occur in many cases.

When do I need to see a doctor with a mold allergy?

Always consult a doctor with symptoms that indicate a mold allergy. If you have only mild symptoms, the doctor may advise observing the development of the symptoms over a period of time in order to arrive at a diagnosis.