Scanning electron micrograph (SEM) of a human eyelash (hair surface) with an unknown fungus infection. This infection is a type of superficial mycoses that is limited to the outermost layers of the hair or skin. The fungus alone has only a minimal capacity to damage skin directly. Superficial mycoses affect approximately 9 million Americans and account for 5% of skin diseases. These fungi invade only the dead or keratinized layers of the skin, hair and nails. However, an impaired immune system can encourage the infecting fungus to proliferate. Magnification: x240 when shortest axis printed at 25 millimetres.