Dermatophytes are unique in that they produce keratinase, which enables them to use keratin as a nutrient source. Infected hairs become brittle, and after three weeks, the clinical presentation of broken hairs is evident.There are three types of infection:
Ectothrix: Characterized by the growth of fungal spores (arthroconidia) on the exterior of the hair shaft. Infected hairs usually fluoresce greenish-yellow under a Wood lamp (blacklight). Associated with Microsporum canis, Microsporum gypseum, Trichophyton equinum, and Trichophyton verrucosum. Endothrix: Similar to ectothrix, but characterized by arthroconidia restricted to the hair shaft, and restricted to anthropophilic bacteria. The cuticle of the hair remains intact and clinically this type does not have fluorescence. Associated with Trichophyton tonsurans and Trichophyton violaceum, which are anthropophilic. Favus: Causes crusting on the surface of the skin, combined with hair loss. Associated with Trichophyton schoenleini. Diagnosis
Tinea capitis may be difficult to distinguish from other skin diseases that cause scaling, such as psoriasis and seborrhoeic dermatitis; the basis for the diagnosis is positive microscopic examination and microbial culture of epilated hairs. Woods lamp examination will reveal bright green to yellow-green fluorescence of hairs infected by M. canis, M. audouinii, M. rivalieri, and M. ferrugineum and a dull green or blue-white color of hairs infected by  T. schoenleinii. Individuals with M. canis infection trichoscopy will show characteristic small comma hairs. Histopathology of scalp biopsy  shows fungi sparsely distributed in the stratum corneum and hyphae extending down the hair follicle, placed on the surface of the hair shaft.
Most women with inverted nipples who give birth are able to breastfeed without complication, but inexperienced mothers may experience higher than average pain and soreness when initially attempting to breastfeed. When a mother uses proper breastfeeding technique, the infant latches onto the areola, not the nipple, so women with inverted nipples are actually able to breastfeed without any problem. An infant that latches on well may be able to slush out an inverted nipple. The use of a breast pump or other suction device immediately before a feeding may help to draw out inverted nipples. A hospital grade electric pump may be used for this purpose. Some women also find that using a nipple shield can help facilitate breastfeeding. Frequent stimulation such as sexual intercourse and foreplay (such as nipple sucking) also helps the nipple protract. Piercing
Another method of protracting inverted nipples is to have the nipple pierced. This method will only be effective if the nipple can be temporarily protracted. If pierced when protracted, the jewellery may prevent the nipple from returning to its inverted state. The success of both of these methods, from a cosmetic standpoint, is mixed. The piercing may actually correct the overly taut connective tissue to allow the nipple to become detached from underlying connective tissue and resume a more typical appearance. Other corrective strategies
Other strategies for protracting inverted nipples include regularly stimulating the nipples to a protruding state, in an attempt to gradually loosen the nipple tissue.