Cladosporium
Definition
Cladosporium is one of the most common molds found indoors and outdoors, according to CDC. Like other molds, it grows on damp surfaces and can trigger allergies in sensitive people.
What it means
Cladosporium is a very common mold genus. CDC names it first among the most common indoor molds, along with Penicillium and Aspergillus. It is also common in outdoor air, which is why it often appears on both the indoor and outdoor samples in a mold inspection report.
Indoors, it grows where moisture lingers. EPA says no mold will grow without water or moisture.
Why it matters to your health and your home
Cladosporium is not a special category of danger. EPA says molds produce allergens and irritants, and allergic reactions to mold are common. They can include sneezing, runny nose, red eyes and skin rash, and mold can trigger asthma attacks in people with asthma who are allergic to it. If an inspection finds high Cladosporium indoors compared with outside, the useful question is where the moisture is coming from. EPA notes that no federal standards exist for judging mold sample results, so ask the inspector to explain what the numbers mean for your home. Our page on mold allergy covers symptoms and testing.
Sources
- Mold (About Mold), Centers for Disease Control and Prevention (September 26, 2024)
- Mold and Health, U.S. Environmental Protection Agency (February 18, 2026)
- Mold Remediation in Schools and Commercial Buildings Guide, Chapter 3, U.S. Environmental Protection Agency (April 29, 2026)
Updated October 19, 2026. Drafted with AI assistance and edited by Vincent Wallace. All glossary terms