You should arrange a professional mould inspection within the next few days. The inspector will use a moisture meter to identify the full extent of the water intrusion—likely condensation from the temperature differential between the AC-cooled room and the humid outdoor air, exacerbated by the wardrobe trapping moisture against the wall. They will also assess whether the growth is superficial or has penetrated the drywall. In villas, this can sometimes indicate a minor leak from a pipe or the AC drain line that has gone unnoticed.

Until the inspection, keep the guest room’s door closed and the AC running on a dry mode to lower humidity. Do not attempt to clean it yourself, as disturbing the patch can release a large number of spores into the air, potentially spreading the contamination to other areas of the house.

A proper remediation plan will be based on the inspection’s findings. For extensive growth, containment of the area with negative air pressure is standard to prevent cross-contamination. The final step should always be post-remediation verification to confirm the spore count has returned to acceptable indoor levels.