Is the Black Mold in My Shower Toxic?

What is a black mold?

Mold in your shower can cause annoying symptoms and health problems in people who are sensitive to it. The color of the mold doesn't have any connection to how dangerous it is.
Mold in your shower can cause annoying symptoms and health problems in people who are sensitive to it. The color of the mold doesn't have any connection to how dangerous it is.

Showers are perfect breeding grounds for mold. Mold thrives in damp areas with poor ventilation. These conditions are often found in bathrooms. Mold needs adequate moisture, oxygen, food, and the right temperature. In these conditions, mold will grow and reproduce by releasing spores, which are microscopic cells that act like seeds. 

When people use the term black mold, they are usually referring to Stachybotrys chartarum, which has been referred to as "toxic black mold." The color of the mold doesn't have any connection to how dangerous it is. 

However, there is no evidence that exposure to any type of mold causes memory loss, trouble focusing, headaches, fatigue, infant pulmonary hemorrhage, which is bleeding into the lungs, or autoimmune disease.

Toxic substances called mycotoxins are released by some types of mold, but mycotoxins are not that harmful when they are inhaled. They are most dangerous when they are eaten.

Although the dangers of black mold have been exaggerated, mold can cause health problems in people who are sensitive to it.

Symptoms of mold exposure

Many types of indoor mold, not just black mold, can cause symptoms in people who are sensitive to it. Mold can also cause symptoms in people who are exposed to it for a long period of time. The following symptoms can occur from mold exposure:

Symptoms of mold exposure may be worse in people who have the following problems:

Causes of mold

Mold will grow anywhere with the right conditions. Mold can grow if the humidity exceeds 70%, and it can be active if the humidity is over 60%. Mold can grow quickly on a damp surface, often within 24 to 48 hours. 

Mold thrives anywhere conditions are dark, warm, and moist. Mold is most commonly caused by water leaks, condensation, and floods in buildings. Areas that are poorly ventilated, such as kitchens and bathrooms, are also prone to mold.

Types of mold

The most common types of indoor mold are:

  • Cladosporium
  • Penicillium
  • Aspergillus 
  • Alternia

When to see the doctor for mold exposure

If you're having symptoms of mold exposure, you may want to see your doctor or allergist to find out if you're allergic to mold. Your doctor can perform some tests to see if you have a mold allergy and work with you to recommend a treatment plan. 


Common Allergies: Symptoms and Signs See Slideshow

Diagnosing mold exposure

Your doctor will talk to you about your medical history and any symptoms you've been having. The following tests can also be used to diagnose mold allergies:

Skin prick test

A skin prick test can determine if you are allergic to a substance by using a small amount of the diluted substance. It's applied via a prick in your skin, and you will develop a small hive around the area of the prick if you're allergic. 

Blood test

The blood test for allergies is called a radioallergosorbent test (RAST). With this test, a small amount of your blood is analyzed for antibodies. These antibodies indicate an allergy to a specific type of mold. 

Treatment for mold exposure in your shower

For any type of allergy, the most important part of treatment is limiting your exposure. If you find black mold in your shower, it can be cleaned with soap and water or a diluted bleach solution. Keeping the shower dry between uses and installing a bathroom fan can help prevent mold. Your doctor may also suggest any of the following treatments: 

Nasal sprays

Nasal sprays containing corticosteroids or antihistamines are often the first line of treatment. They can help reduce the inflammation caused by allergies. Some, such as fluticasone, can be bought over-the-counter. Others, such as Azelastine, must be prescribed by your doctor. 

Allergy medications

Antihistamines such as cetirizine or loratadine are often used to treat allergies. They work by blocking histamine, a chemical that is released by your immune system when you are exposed to something you are allergic to. 

Montelukast is a prescription allergy medication that works by blocking leukotrienes, another chemical released by your immune system in response to an allergen

Sinus rinses

Saltwater rinses can help flush away irritants such as allergens from your nose. This can help eliminate your allergy symptoms. There are kits available over the counter that contain the saline mix. It's important to use distilled water and make sure all of the parts of the kit are cleaned and dried between uses. 

Allergy shots

Immunotherapy, or allergy shots, help build your immunity by exposing you to a small amount of an allergen. These are only used for certain types of mold. 

Asthma and Allergy Foundation of America: "Mold Allergy."

Centers for Disease Control and Prevention: " Facts about Stachybotrys chartarum."

Clinical Reviews in Allergy and Immunology: "Mold and Human Health: A Reality Check."

Clinical Reviews in Allergy and Immunology: "The Myth of Mycotoxins and Mold Injury."

FEMA: "Dealing with Mold and Mildew in Your Flood Damaged Home."

Indoor Air: "Indoor mold levels and current asthma among school-aged children in Saskatchewan, Canada."

Integrated Medicine: A Clinician's Journal: "Is Mold Toxicity Really a Problem for Our Patients? Part 1 - Respiratory Conditions."

Institute of Medicine (US) Committee on Damp Indoor Spaces and Health. Damp Indoor Spaces and Health. National Academies Press. 2004

Mayo Clinic: "Mold Allergy."National Institute of Environmental Health Sciences: "Mold."

Virginia Cooperative Extension: "Mold Basics."