Picture of Hyperhidrosis: Starch-Iodine Test
Hyperhidrosis is a condition that causes excess sweating. Approximately 2% to 3% of people in the U.S. suffer from the condition. Excess sweating may occur under the arms (axillary hyperhidrosis) or on the soles of the feet and palms of the hands (palmoplantar hyperhidrosis). The latter tends to occur first in childhood where excessive underarm sweating most often manifests during puberty. The photo depicts a starch-iodine test displaying blue-black discoloration in areas responsible for excess sweating.
Text Reference: American Academy of Dermatology: "Hyperhidrosis"