What personal hygiene covers

Two kinds of gland make the raw material of body dirt. Eccrine glands are spread over almost the whole body surface, with the highest density on the palms and soles, and they pour out a watery, salty sweat that cools the body by evaporation. Apocrine glands open into hair follicles in the axillae, the groin and around the nipples, and they become active at puberty; their secretion is rich in proteins and lipids and is odourless as it leaves the gland. The smell comes later, when resident skin bacteria — mainly Corynebacterium and Staphylococcus species — break those compounds down into volatile fatty acids. That is why the underarms, groin and feet smell first, and why washing, drying and clean clothing work better than perfume. Sebaceous glands secrete sebum, an oil that keeps skin and hair supple but also glues dirt and dead corneocytes to the surface. The skin also maintains an acid mantle, a slightly acidic film with a pH of about 4.5 to 5.5 that restrains pathogens. Harsh soap, scrubbing and repeated wetting raise that pH and strip the lipids of the barrier. Drying is therefore not cosmetic: moisture left in a skin fold or between the toes softens the stratum corneum, a process called maceration, opens tiny cracks and gives dermatophytes the warm, damp conditions they need. The rule — remove sweat, sebum, dead cells and microbes, rinse, then dry — is identical at every site; only the tool, the frequency and the threat change.

The mouth is the area of the body most prone to collecting harmful bacteria. It mechanically breaks food into pieces, and the debris that remains sticks to the gums and teeth. The mouth cavity is warm, moist and rich in nutrients, so bacteria grow on that debris and build plaque, a sticky deposit that clings to the tooth surface. Plaque is soft and can be brushed away, but if it is left in place the minerals dissolved in saliva — calcium and phosphate — are laid down inside it and set it into tartar, a hard, yellowish, calcified layer that a toothbrush cannot remove and that only professional scaling can clear. The consequences follow in order: tooth decay, infection of the gums and halitosis, the unpleasant breath also called stinky odour. The hand works by a different route but the same logic of removal. Soap is a surfactant: one end of the molecule mixes with water and the other with fat, so it lifts oily dirt and the microbes bound to it from the skin. Friction rubs the loosened material free and rinsing carries it away, which is why a quick rinse under the tap is not handwashing. The notes list the critical situations that put pathogens on the hands: after using the toilet or handling faeces or a nappy, after touching raw meat, before preparing or eating food and before feeding a child, after contact with rubbish bins or cleaning cloths, after handling animals, and after blowing the nose. In health care the list continues: before and after touching a wound, after contact with blood or body fluids, before and after dressing a wound, before caring for an at-risk person, and after caring for an infected person. Tying each action to its moment is what makes hand hygiene effective, and a nurse also performs mouth care for patients who cannot brush their own teeth, because plaque and tartar form just as quickly in a dependent patient.

Nails, hair and ear wax are not dirty in themselves; they become a hygiene problem because each one creates a protected space where secretions and debris collect out of sight. A nail is hard keratin that grows continuously, and the space beneath the free edge is warm, dark and moist — an ideal nursery for bacteria and fungi. Fingernails therefore trap dirt that may come from defecation or from touching contaminated surfaces, which is why they are kept trimmed short along their natural shape, without cutting so close that the skin is damaged, and why weekly care is the usual rhythm. Nail cutters and scissors must not be shared, because fungal spores and blood-borne viruses can survive on them. The scalp has sebaceous glands that oil the hair and numerous sweat glands, and dead skin cells accumulate there too; oil, sweat and dead cells together make hair greasy unless it is washed regularly, at least twice weekly. Poor hair hygiene is linked to dandruff, in which an overgrowth of the yeast Malassezia and excess sebum produce visible flakes, and to Tinea capitis, a dermatophyte infection of the scalp. Head hair is also the habitat of Pediculus humanus capitis, the head louse, and of nits, its eggs; lice spread by close head-to-head contact, which is why children in schools are affected so often. They cause itching, irritation and embarrassment, and heavy infestation may require shaving the head, but blades are never shared. The ear canal produces cerumen, or ear wax, a secretion that traps dust and has protective properties. Daily washing of the outer ear with soap and water is enough. Nothing should be pushed deeper than a little finger: hairpins, safety pins and blunt objects can injure the canal or the tympanic membrane, and cotton buds can push wax into an impaction. If wax blocks the ear and interferes with hearing, the patient is referred rather than probed.

Clothing is the layer that decides whether skin secretions stay on the skin or are carried away. Underwear, vests and T-shirts sit directly against the body and absorb sweat and dead skin cells, which stain the cloth; bacteria then grow on that dirt and add their own smell to the odour of sweat. Underwear must therefore be washed more often than the outer layer and changed daily. Soiled clothing needs adequate clean water, detergent and a place to wash, and washed clothes should be dried thoroughly and ironed where possible, because heat helps destroy body lice and nits; boiling water or insecticides can clear an infestation. The feet combine a high density of sweat glands with shoes that hold moisture in. That warm, damp environment favours dermatophytes, the fungi that cause tinea pedis, or athlete’s foot — scaly skin, sores and blisters that begin between the toes and can spread to the soles. The cracks are usually minor and settle by themselves, but they can become the entry point for bacterial infection, so the feet are washed daily or at least twice weekly and dried carefully between the toes, with clean socks and rotated shoes. Feet also matter in podoconiosis, or mossy foot, a reaction to very fine soil particles that pass through the skin of bare feet and cause swelling of the feet and lower legs; it is common in certain highland areas of Ethiopia, is prevented by wearing shoes at all times and, once present, is treated with careful washing, drying, elevation and compression. Menstrual hygiene is the last flow to manage. The vagina cleans itself, so no internal washing is needed; the outer genital area is washed daily with clean water. Sanitary pads and tampons are changed regularly, hands are washed before and after handling them, and clean, soft cloths may replace pads, though dirty cloths must never be used. Absorbent items are disposed of properly, for example in a burial pit, not in a latrine or in water, and this routine protects comfort, infection risk and dignity. Anal cleansing after defecation follows the same principle: clean toilet paper or water is used, hands are washed with soap afterwards, and rags, leaves, stones, corn cobs or sticks are discouraged because they damage the skin.