Essential Fatty Acid Deficiency (EFAD)
Essential fatty acid deficiency (EFAD) is a metabolic disorder that develops when the body does not get enough of the two polyunsaturated fatty acids (PUFAs) that humans cannot make for themselves: linoleic acid (LA, omega-6) and alpha-linolenic acid (ALA, omega-3).
Because the epidermis turns over its lipids very quickly and relies entirely on dietary fatty acids to build its lipid layers, the skin is the first and most severely affected organ in EFAD. Typical signs include a badly weakened skin barrier, increased transepidermal water loss (TEWL), dry fish-scale (ichthyosis-like) skin, red, eroded skin in body folds and slow wound healing.
At Haute-Derma, we take a comprehensive diagnostic and treatment approach: measuring the serum fatty acid profile (triene:tetraene ratio), assessing skin barrier function with a dedicated TEWL meter, and combining systemic fatty acid replacement with topical lipid therapy (topical EFAD therapy) to restore the epidermal barrier quickly.
Clinical Background and Skin Pathophysiology
Causes and How the Epidermal Lipid Barrier Breaks Down
- Disrupted acylceramide (ceramide EOS) synthesis:
- Linoleic acid (LA, 18:2 n-6) is the key building block of acylceramide (ceramide 1 / ceramide EOS), made in the lamellar (Odland) bodies of the granular layer.
- Without enough LA, the body is forced to substitute oleic acid (OA, 18:1 n-9). This weakens the lipid lamellae of the stratum corneum and breaks the integrity of the barrier, so transepidermal water loss (TEWL) jumps 3–5-fold.
- Mead acid build-up and an abnormal triene:tetraene ratio:
- When linoleic acid is lacking, the enzyme delta-6 desaturase switches to oleic acid and produces Mead acid (eicosatrienoic acid, 20:3 n-9, a triene).
- Normally, linoleic acid is converted into arachidonic acid (20:4 n-6, a tetraene).
- The gold-standard biochemical marker for EFAD is a triene:tetraene ratio > 0.2 (or > 0.4 by some laboratory standards).
- Reactive epidermal hyperplasia: acute water loss through the skin drives keratinocytes to overproliferate without time to fully differentiate, causing thickened skin and fish-scale (ichthyosiform) desquamation.
Common Clinical Causes of EFAD
- Lipid-free total parenteral nutrition (TPN): ICU or post-bowel-surgery patients on long-term TPN without an intravenous lipid emulsion (IVLE).
- Malabsorption and gastrointestinal surgery: cystic fibrosis, short bowel syndrome, chronic inflammatory bowel disease (Crohn's disease), or after bariatric surgery.
- Extreme fat-restricted diets: children or adults eating an almost fat-free diet for long periods.
Typical Skin Manifestations
Severe Xerosis and Ichthyosiform Scaling
- Appearance: the skin all over the body becomes dry and rough, loses its natural sheen and sheds fine white or ash-gray scales.
- Location: most obvious on the trunk, limbs and face. Facial skin may be slightly red and sting on contact with water or ordinary cosmetics.
Intertriginous Erythematous Dermatitis
- Lesions: red, eroded, slightly weeping patches in body folds (armpits, groin, under the buttocks, neck, and the diaper area in children) that peel easily with friction.
- Common misdiagnoses: easily mistaken for seborrheic dermatitis, atopic dermatitis or zinc-deficiency acrodermatitis enteropathica.
Hair and Nail Changes and Slow Wound Healing
- Hair loss (alopecia): thin, dry, brittle hair that breaks easily, with diffuse shedding across the scalp; eyebrows and eyelashes may also fall out.
- Nails: thin fingernails that split into layers and grow slowly.
- Wound healing: reduced cell renewal and prostaglandin production, due to a lack of arachidonic acid, make wounds slow to heal and prone to becoming chronic ulcers.
Higher Risk of Secondary Skin Infection: the collapse of the skin barrier lets bacteria (Staphylococcus aureus) and Candida yeast invade, causing pustular dermatitis or persistent intertrigo.
How We Diagnose EFAD at Haute-Derma
Haute-Derma combines clinical assessment with laboratory testing to diagnose EFAD accurately:
- Nutritional history and skin barrier measurement:
- A review of any intravenous feeding, gastrointestinal surgery or restrictive diets.
- A Tewameter to measure transepidermal water loss (TEWL), plus corneometry for stratum corneum hydration.
- Serum fatty acid profile:
- Linoleic, oleic, arachidonic and Mead acid levels measured by gas chromatography-mass spectrometry (GC-MS).
- Calculation of the triene:tetraene ratio (Mead acid / arachidonic acid). A value > 0.2 confirms EFAD.
Telling Nutritional Deficiency Dermatoses Apart:
| Condition | Key Biochemical Marker | Distinguishing Clinical Features |
|---|---|---|
| Essential fatty acid deficiency (EFAD) | Triene:tetraene ratio > 0.2; low blood linoleic acid | Generalized dry, fish-scale skin, eroded dermatitis in body folds, dry brittle hair loss. |
| Zinc deficiency (acrodermatitis enteropathica) | Low serum zinc (< 70 µg/dL) | Red, scaly patches around body openings (mouth, anus, genitals) and on the fingertips and toes. |
| Niacin deficiency (pellagra) | Low urinary N1-methylnicotinamide | Burning redness on sun-exposed skin (face, neck, forearms; Casal's necklace). |
| Atopic dermatitis | Raised total IgE; family history of allergy | Intense itch, red patches in the elbow and knee creases, chronic dry skin. |
Treatment and Skin Barrier Repair
Treating EFAD requires both systemic fatty acid replacement and topical lipid therapy (topical EFAD therapy):
Systemic Lipid Repletion
- By mouth / feeding tube: plant oils rich in linoleic and alpha-linolenic acid, such as safflower oil, sunflower seed oil or soybean oil (10–20 mL/day).
- Intravenous (IVLE): a 10–20% lipid emulsion (such as Intralipid or Smoflipid) at least 2–3 times a week for patients on TPN.
Topical Lipid Therapy (A Clinical Breakthrough)
- How it works: linoleic acid applied to the skin is absorbed through the stratum corneum directly into keratinocytes, where it is used right away to make ceramide EOS, bypassing the gut entirely.
- Topical LA-rich plant oil: pure cold-pressed sunflower seed oil (> 60% linoleic acid) applied directly to dry, scaly areas 2–3 times a day.
- Multilayer Barrier Repair Cream: an intensive moisturizer with a physiologic ceramide : cholesterol : free fatty acid ratio (3:1:1), plus 2% linoleic acid, 4% niacinamide and zinc oxide, soothes raw, peeling skin and brings TEWL back to normal.
