For these 8 weeks, we’re going ‘intensive’ into skin facts. Many articles have shared about adult skin facts, but in #SkinishMom style, we’re ‘digging’ deeper into children’s skin and eczema skin. (Note: all skin facts have published data for children and eczema skin)
Skin Fact #1 Skin is (NOT!) the largest organ in the body
Oops, doesn’t everyone say that skin is the largest organ? That’s why some ‘skin’ investigation is required for ‘skin journalism’. Located a letter to editor in the Journal of Investigative Dermatology that skin is not the largest organ in the body. The skin can be considered the largest BY WEIGHT for ‘medium-sized’ organs, excluding musculoskeletal system.
- Skin (epidermis and dermis) weights 3.86kg, about 5.5% of a 70kg man
- Subcutaneous tissue (layer of fats under the dermis layer) is not consider skin
- Skin is not the largest organ by surface area, about 1.7 sqm but lung airway is 70sqm, and gastrointestinal tract is about 30-40sqm (note in the letter to editor, it’s stated as about football field, but in a paper that subsequently published in 2014 Scandinavian Journal of Gastroenterology, scientists measured the inner surface of gastrointestinal tract of a healthy average man; previous estimates of the gastrointestinal tract were made post-mortem where the tract has relaxed to a much longer length! ‘Interesting!’)
Skin Fact #2 Adult skin sheds about 17kg to 52kg over a lifetime
From research and as explained by Dr Claudia Aguirre on Quora (Dr Claudia is a featured guest of this blog), humans shed their entire outer layer of skin every 2-4 weeks at the rate of 0.001 — 0.003 ounces of skin flakes every hour. This worked out mathematically to be 17kg to 52kg (or 37 to 115 pounds) for someone who live up to over 70 years old (I’d suppose that the 0.001 to 0.003 ounces is for an average adult, thus strictly speaking, you can’t simply multiply by 70 due to (possibly?) less skin shed for a child (by weight, but given larger surface area to volume ratio, a child may shed ‘more’ skin).
Eczema skin – Eczema skin, characterized by dry skin, shed more skin (and add the scratching!). The outer skin layer (epidermis) has four layers of keratinocytes (skin cells). The keratinocytes at the basal layer continually grow and move upwards to the stratum corneum, changing from plump cells to dead, flattened cells that are shed. This takes about 28 days. I couldn’t find research on how much skin an eczema sufferer shed, but there’re two ‘opposite’ skin conditions worth mentioning:
Exfoliative Dermatitis – characterized by extensive red skin, followed by skin shedding (similar to life-threatening conditions covered in this blog: Stevens Johnson Syndrome and Erythroderma); the skin shedding is so extensive in these conditions that it affect the normal functioning of the body, in particular temperature regulation and moisture retention, requiring care in hospital.
Psoriasis – this condition is marked by only taking 3 to 4 days to mature and does not shed but the skin cells pile up on the skin surface, forming plaques and lesions.
Many eczema sufferers reported seeing massive skin shed on the bed and floor but I wonder why the skin cells shed appear so visible (as opposed to normal skin). Found an explanation that the cells on dry skin may stick together, thickening the stratum corneum and when they are shed, it is shed as visible sheets, aka scales.
Skin Fact #3 Dead skin cells comprised an UNKNOWN part of our dust at home
This is another ‘fact’ that could turn out to be a myth – most of the sites state that our dead skin made up anywhere from 50% to 90% of our dust at home. In a study by Layton and Beamer whose study was to find out how much of contaminated soil and outdoor pollutants would get into home dust, it was estimated that about 60% would come from outdoors. Dust is very complicated, with different home, season, surrounding and the type of dust in the air and on the floor being different. It cannot be simplified to state as most of the dust are dead skin cells.
What we have to know is dead skin cells are food for house dust mites and they literally sleep with us, in our bedsheet, pillow, pillow case and mattress. Read the following posts to understand more about dust mites:
- House dust mites and eczema child
- Minimizing indoor house dust mites
- Research news on house dust mites (even eczema children not sensitized to dust mites showed worsening eczema with contact with dust mite allergen)
- Dust mites in car seat
There’s sooo much more skin facts to cover, I think we’re good for discovering these till end of the year!
- Journal of Investigative Dermatology September 2013 ‘Letter to Editor’
- Scandinavian Journal of Gastroenterology June 2014 Surface area of the digestive tract – revisited.
- Clinical Pharmacist September 2010 Atopic eczema: Clinical features and diagnosis
- Healthline: Exfoliative dermatitis
- Dermal Institute: the Biology behind Eczema and Psoriasis
- PDR Health: Dry skin
- Environmental Science and Technology November 2009: Migration of Contaminated Soil and Airborne Particulates to Indoor Dust
- Time February 2010 What’s in Household Dust? Don’t Ask