How Mold Can Cause Hives: Allergen Explained

An allergic reaction to an allergen can have many different symptoms, including hives. One of the most common airborne allergens are mold spores. For people who are allergenic to mold, symptoms can be acute as well as chronic.

Various factors cause hives or urticaria, and the most prevalent trigger is due to an allergic reaction. Molds can induce allergic reactions and cause hives. An allergic response to mold can be from inhalation, skin contact, or ingestion.

What are Hives?

Urticaria or hives are raised blotches or bumps on the skin resulting from allergies, chronic medical conditions, or trauma. They are usually red or stay the same color as the skin, and usually itch and burn. The patterns of the welts vary, either concentrated in one area or all over the body.

Hives can be debilitating. Urticaria is one of the allergic diseases classified as severe. People who suffer from hives report that it interrupts all aspects of their lives and their overall well-being. Hives can occur with angioedema. Which is the swelling of the mucus membranes beneath the skin. Angioedema can be on the lips, face, throat, eyelids, abdomen, or extremities.

Common Allergens that Cause Hives

  • Molds
  • Food (shellfish, nuts, dairy, etc.)
  • Pollens
  • Dust mites
  • Medicines
  • Insect bites
  • Animal fur

Other Causes of Hives

  • Extreme temperature (too hot or too cold)
  • Trauma (even a light pat can cause welts in some people)
  • Chronic diseases that compromise the immune system (hepatitis, thyroid issues, cancer, HIV, lupus, etc.)

Acute vs Chronic Hives

Acute hives occur suddenly and last less than six weeks, as is the case in most allergic reactions.

Hives are considered chronic when they last for more than six weeks. Chronic cases of hives can even occur monthly or over the course of several years.

Most hives caused by molds are acute. However, there are cases when constant exposure to mycotoxins results in lifetime chronic urticaria.

The causes of acute hives are easier to identify because you can trace recent exposure. In contrast, the causes of chronic hives are much harder to detect.

How Molds Cause Hives

mold growth pot

Molds have been identified as one of the probable causes of allergic reactions leading to hives.

Florida-based mold removal company Water Mold Fire explains that not all molds are toxic. Mold spores are everywhere, and most people are not adversely affected by them.

However, people with mold sensitivities need to be aware of their surroundings to minimize or ideally avoid exposure.

Studies show that urticaria and dermal reactions are commonly associated with mold sensitivities. Clinical allergic conditions caused by molds are more severe.

Why Are Some People More Sensitive to Mold?

Some people’s immune systems are more sensitive than others’. If a person is predisposed to allergies, their immune response to certain substances is more severe.

As discussed, some species of mold are not toxic in itself. However, people with mold sensitivities will have allergic reactions to molds not classified as "black molds" or "toxic molds."

Mold sensitivities could be due to genetics, prolonged exposure, or chronic disease.

What is benign to one person, can be hazardous to another. This is true not just for mold allergies, but for any allergen.

Ways Mold Cause Hives

Molds can pose a risk as a result of inhalation or skin contact.


Inhalation is the most frequent cause of allergic reactions to molds. The mold spores are micro-scopic in nature and remain undetected until people start developing allergies like hives or they start feeling ill.

A study conducted on patients with urticaria found that inhaled allergens are the most common component for its development—more than food allergens.

It is worth noting that inhalation doesn't just happen from spores that are suspended in the air. Be careful, too, of molds on surfaces and materials you come in close contact such as bed linens, clothes, and even food.

Skin contact

Our skin is the biggest organ of the body. When mold spores come in contact with the skin, most people will remain unaffected.

However, people with mold allergies are susceptible to allergic reactions in the form of hives or dermititis.

woman cleaning window

Prevention and Treatment of Hives Caused by Mold

Minimize exposure to mold

Molds thrive in warm, humid environments. Prevention of mold growth will reduce exposure and related health issues.

If you live in the area where the climate is conducive to mold growth, take the necessary precautions.

  • Make sure to address any water damage in the home as it can be a breeding ground for mold.
  • Keep vents and air conditioning units clean. Maintain them well to avoid mold growth.
  • Keep the air at home relatively dry and cool. If you have mold sensitivities, invest in a good dehumidifier to keep humidity at a minimum.
  • Wash fruits and vegetables thoroughly. As mentioned above, food-stuffs could contain mycotoxins and cause an allergic reaction when ingested.
  • Keep your home clean, especially wet and humid areas like the bathroom and basement. Change bed sheets and linens often.

Diagnosis and Treatment of Hives Caused by Mold

If you suspect that mold is a contributing factor to your hives, consult a Allergist or Immunologist. Allergic diseases caused by molds are still widely underdiagnosed.

An Allergist is able to order the appropriate skin or blood tests to confirm your suspicions. Blood tests measure the level of antibodies specific to allergens like mold.

Some doctors may prescribe oral or topical antihistamines to treat hives.

Do not use home remedies without consulting a qualified medical professional.

Robert Woods
At POP, we strive to provide practical preventative advice. We strive to figure out ways to prevent problems that people might have trouble grasping. We've found that other sources have trouble articulating concepts in a way that regular people can understand.
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