Hair and Scalp Care and Disorders
Divide this domain into hair analysis, scalp care, and recognition of disorders you must refer.
Hair analysis covers texture (fine, medium, coarse), density, porosity (how readily hair absorbs moisture), elasticity (stretch and return), and growth pattern. Porosity and elasticity determine which chemical services are safe; brittle, low-elasticity hair is a warning sign.
Scalp care in barbering means cleansing, conditioning, and massage - not diagnosis. Shampoos are surfactants that lift sebum and debris; conditioners are typically cationic and smooth the cuticle. Scalp massage follows the direction of venous flow and uses gentle, controlled pressure.
Disorders to recognize: dandruff (pityriasis) and seborrheic dermatitis are non-contagious scaling conditions; psoriasis shows thicker plaques; tinea capitis is a fungal infection with scaling and broken hairs and is contagious; pediculosis (lice) is contagious; folliculitis and furuncles are bacterial infections of the follicle; alopecia areata is an autoimmune, non-contagious patchy loss; androgenetic alopecia is patterned loss; telogen effluvium is diffuse shedding after stress or illness. Hair-shaft disorders include trichorrhexis nodosa (nodes that fracture), monilethrix (beaded shaft) and fragilitas crinium (split ends).
Traps: confusing tinea capitis with dandruff, calling alopecia areata contagious, or claiming a barber may treat lice or infection. The barber's job is recognition and referral.
Rule of thumb: red, swollen, oozing, broken skin, fever, or a spreading ring of scale means stop and refer. Non-infectious scaling can be serviced with appropriate products.