Cladosporium Mold: Identification, Health Effects, and Removal

What it is

Cladosporium is the most common indoor mold on earth, so common that its spores are a normal part of the air both outdoors and inside. It ranges from olive to a dark green-black and has a suede-like surface. For most people it is an allergen rather than an infectious threat.

It stands out among household molds for tolerating cooler temperatures, which is why it colonizes places other molds avoid, such as refrigerator seals and cold window gaskets. It rarely invades tissue, so a small Cladosporium patch is generally a cleaning task rather than a medical one.

Where it grows

Typical homes are window frames and sills where condensation collects, bathroom corners and grout, fabrics, and shaded damp walls. Because it handles cold and moderate dampness, it appears in spots that stay cool and slightly humid rather than requiring the heavy saturation that black mold needs.

Health effects

Cladosporium is a very common allergen and asthma trigger. Its effects are the familiar allergy pattern of sneezing, congestion, itchy and watery eyes, and irritated airways, which flare when spore counts rise. People with asthma or mold allergy react more strongly.

It rarely causes infection in healthy people. The main reason to remove it, beyond appearance, is to reduce the allergic and asthma burden for the people living with it and to address the moisture that allowed it to grow.

How to remove it

On non-porous surfaces such as glass, tile, and sealed frames, Cladosporium wipes away with detergent and water, and it stays gone once the surface is kept dry. Improving ventilation and cutting condensation on cold surfaces is the durable fix.

Where it has grown into porous material such as fabric or soft caulk, that material is often easier to replace than to fully clean. Persistent growth signals a condensation or humidity problem that needs correcting.

For the full method, see our mold removal guide and the guide to black mold remediation.