Temporary hair loss after bariatric surgery
Although not essential for health, scalp hair can be important for self-image and hair loss or alopecia can cause significant psychological distress. Some degree of hair loss is relatively common after bariatric surgery, usually occurs 3 months or more after surgery and affects about one third of all patients. The precise causes of postbariatric hair loss are unknown; It is believed that factors that include changes in nutritional status and the impact of surgery on the hair growth cycle are involved. In most cases, the hair will begin to grow again without intervention once the weight has stabilized.
How is human hair made up
Human hair is mainly composed of the keratin protein; It also contains lipids, water, pigments and metal trace elements. Each individual hair comprises a strand that extends over the skin from a root embedded in a bag called a follicle, which has a lower, middle and upper segment. A structure called dermal papilla is found at the base of the lower segment or bulb. Formed from connective tissue, it supplies the hair with nutrients from the bloodstream. In the scalp hair also contains receptors for steroid hormones, known as androgens, that regulate hair growth.
Each strand of hair comprises several layers. The medulla is a central nucleus. Absent of thinner hairs, its role is not fully understood. The middle layer or bark occupies the largest proportion of the hair shaft. It contains bundles of keratin filaments that give hair flexibility and tensile strength. The bark also contains pigment granules such as melanin that provide color. The cuticle is a translucent and colorless outer layer of overlapping scales that protect the cortex.
The hair growth cycle
Hair growth on the scalp generally follows a three-stage cycle. During the anagen or growth phase, cell division (mitosis) in the papilla is added to the length of the hair shaft, pushing new growth upwards from the root. Anagen can last from 2 to 10 years, although it is more typical from 3 to 5 years, during which the hair can grow at a rate of up to half an inch (1.25 cm) per month. Duration and growth rate may be influenced by age, genetics, hormones and metabolic factors, and may be sensitive to seasonal changes and circadian rhythms. In general, between 80 and 90% of scalp hairs will be in anagen at any time.
At the end of the anagen phase, the hair enters a transition period called a collagen. During this phase, mitosis ceases and the hair follicle contracts, cutting off the nutrient supply from the papilla to the root. The marrow and cuticle formation end first, leaving a section of the exposed cortex at the end of the hair shaft root. This is sealed to form a rounded hair that moves up from the bulb to the upper segment of the follicle, where it is anchored. Catagen is the shortest phase of the hair cycle, lasting 1 or 2 weeks, and only 1% of the hairs are in this phase at any time.
Telogen, the resting phase, now continues. The hair follicle remains inactive for 1 to 4 months until the anagen begins again and the new growth of the hair at the root causes the hair to be expelled from the follicle in a process known as detachment.
A healthy human scalp contains approximately 100,000 hairs, of which around 100 will be shed every day. Each hair remains in the scalp for 1 to 6 years, and continuous new growth occurs to replace lost hairs with normal shedding.
Pathophysiology and diagnosis of hair loss
Postbariatric hair loss usually occurs 3 to 6 months after surgery, and may persist for 6 to 12 months or more, depending on the underlying cause. The diagnosis is usually based on the medical history and clinical examination, with patterns and appearance of hair loss, concomitant symptoms such as skin and nail abnormalities, and the use of potentially important medications.
Several tests can be performed if there are doubts about the nature or cause of hair loss. These may include a biopsy of the scalp to remove follicles for a microscopic examination; blood tests to investigate nutritional deficits, hormonal imbalances or disease states; and tricoscopy, in which an instrument called a dermascope is used to examine hairs in situ at high levels of magnification.
Hair Loss Subtypes
As the majority of scalp hair is in anagen at any time, daily shedding of hair after telogen is not usually noticeable. Telogen effluvium is a condition in which more hairs than normal enter telogen simultaneously. The result is an overall thinning of hair rather than bald patches.
It can be caused by physiological or psychological stress, with potential triggers including surgery, childbirth, rapid weight loss, medication use, hormonal changes, chronic illness, hypothyroidism, and malnutrition. Surgery requiring anaesthesia is particularly associated with telogen effluvium: Anaesthesia is understood to send some anagen hair follicles into premature telogen by blocking the rapid cell division required to sustain hair growth. Because telogen can last for several months, there is usually a delay between the trigger event and onset of hair shedding.
Alopecia areata is a chronic inflammatory condition of unknown etiology, typified by recurrent, patchy hair loss. An autoimmune pathway has been proposed, and there is evidence to suggest a role for genetic factors.
Affected follicles are not destroyed, and hair will often regrow spontaneously, although the new hair growth may sometimes display altered pigmentation.
Androgenetic alopecia, also known as male pattern baldness, can affect men and women. In men, a receding hairline is typical, whilst diffuse thinning of hair is more common in women. Elevated androgen levels at the papilla can shorten anagen and progressively reduce hair shaft diameter, length and pigmentation until the follicle ceases hair production entirely.
Androgenetic alopecia is heritable. It is also associated with metabolic conditions including insulin resistance, polycystic ovarian syndrome (PCOS) and diabetes.
Nutritional Deficiency as a Potential Cause of Hair Loss
If hair loss first occurs more than 6 months postoperatively, or persists for more than 12 months after surgery, dietary causes may be implicated. Rapid weight loss is a known trigger for telogen effluvium, but specific nutritional deficits can also result in hair loss. Hair loss associated with micronutrient deficiency often manifests in parallel with other symptoms, such as skin or nail abnormalities.
Zinc is an essential mineral found naturally in many foods, including red meat, poultry, beans and nuts. Zinc deficiency can be caused by inadequate intake or absorption. In addition to hair loss, it is associated with impaired immune function, poor wound healing and skin lesions.
Zinc is involved in various processes related to the hair cycle including cell division and protein synthesis. It also regulates the signaling pathway that controls transition from telogen to anagen. Zinc deficiency is associated with telogen effluvium and alopecia areata, and may also cause growth of thin, white hair that breaks easily.
Bariatric surgery is considered a risk factor for zinc deficiency – gastrointestinal changes can decrease absorption, and calorie-restricted diets can provide insufficient intake. Diabetes, sickle cell disease and other chronic conditions are also associated with zinc deficiency.
Iron is required to form hemoglobin, a chemical found within red blood cells that carries oxygen from the lungs to the rest of the body. Low levels of hemoglobin or reduced red blood cell count due to lack of iron are classified as iron deficiency anemia. Premenopausal women are particularly susceptible due to pregnancy and menstrual blood loss, whilst iron deficiency anemia in men and postmenopausal women is most likely to occur due to gastrointestinal bleeding or malabsorbtion. RYGB surgery can impair iron absorption, and post-bariatric dietary restrictions may lead to reduced intake.
Symptoms of iron deficiency anemia can include tachycardia (abnormally high heart rate), fatigue and breathlessness, but even when anemia is not present, low iron levels may be associated with impaired keratin production and have been linked to telogen effluvium, alopecia areata and androgenic alopecia. However, reports in the literature are conflicting and the exact role of iron in hair loss remains unclear.
Biotin is a B-complex vitamin sometimes referred to as B7 or vitamin H. It is involved in converting carbohydrates to glucose, metabolizing fats and protein, and supporting healthy skin, hair and nail growth. As a water-soluble vitamin, it is not stored within the body, but is present in small quantities within a wide variety of foods (including egg yolk, soybeans, bananas and whole grains) and is also produced by gut flora.
Biotin deficiency is extremely rare. It has been associated with antiepileptic medications, malabsorbtive conditions such as Crohn’s disease and long term reliance on parenteral nutrition. One study of patients receiving parenteral nutrition described hair loss that displayed rapid improvement on introduction of a biotin supplement. However, despite anecdotal reports of reduced post-bariatric hair loss in individuals taking biotin supplements, a direct link between bariatric surgery and biotin deficiency has not been established.
Amino acids are chemical building blocks that combine to form proteins. Some are synthesized within the body, whilst others, classified as essential amino acids, must be derived from food sources. Digestion breaks down food proteins into their component amino acids, so that they can form new proteins and be used to support processes including tissue growth and repair.
As hair is predominantly composed of keratin, a diet lacking in protein (in particular the essential amino acid L-lysine, found in meat, fish and eggs) can affect hair growth. Hair loss following insufficient protein intake is associated with telogen effluvium. Individual hairs may also display reduced elasticity, strength and diameter, and exhibit color changes, with brown hair becoming blonde, and red or blonde bands appearing in darker hair.
Essential Fatty Acids
Linoleic acid and alpha-linoleic acid belong to the omega-6 and omega-3 groups of fatty acids respectively, and are considered essential to human health. They cannot be internally synthesized and must therefore be obtained from dietary sources such as fish, flaxseed and leafy vegetables.
Essential fatty acid deficiency has been reported in individuals who have undergone gastrointestinal procedures that affect lipid metabolism, such as the Roux-en-Y gastric bypass (RYGB) and adjustable gastric banding. It is associated with skin lesions, hair depigmentation, and loss of scalp and eyebrow hair.
Copper is an essential trace element. Involved various processes within the brain and central nervous system, it is required for iron metabolism, immune system function, connective tissue formation and melanin production. Copper deficiency is rare, but has been observed in some individuals following gastric bypass surgery. Symptoms of copper deficiency may include neurological problems such as gait abnormalities, loss of sensation and visual disturbances. There are reports of alopecia areata directly associated with copper deficiency, and as copper is essential to iron absorption, inadequate levels may lead to iron deficiency anemia, with concomitant hair loss.
Levels of various other micronutrients including niacin (B3), selenium and vitamins A, B12, C and D may be negatively affected by bariatric surgery and have been associated with altered patterns of hair growth.
Management of Hair Loss after Bariatric Surgery
Conservative treatment is most commonly indicated as post-bariatric hair loss is usually temporary. In most cases, regrowth will commence within a few months after cessation of rapid weight loss. Infrequently, hair loss that persists for six months or more may be indicative of a potentially treatable underlying cause.
Additional Dietary Supplements have not been proven to work
Addressing a specific nutrient deficiency associated with reversible hair loss can be effective in promoting regrowth but it is important to note that no supplement has been conclusively proven to prevent or treat post-bariatric hair loss. Several studies have examined supplementation with oral iron, zinc or biotin as a prophylactic against hair loss; others have investigated micronutrient supplements or topical preparations such as zinc shampoo for treatment of hair loss in individuals without corresponding clinical nutrient deficiencies. These have been largely inconclusive.
Ingesting additional quantities of water-soluble nutrients such as biotin may not afford any benefits in terms of hair loss but is considered relatively safe. Conversely, excessive supplementation with iron, zinc or copper can cause toxic effects. Ensuring adequate nutrition by adhering to an appropriate post-bariatric diet and supplement regimen will reduce the risk of hair loss and support overall wellbeing.
Minoxidil, also known as Rogaine, Regain or Loniten, is a vasodilator antihypertensive drug thought to stimulate hair growth by lengthening anagen and improving blood flow to the hair follicles. It is available as a topical treatment for androgenic alopecia and its use has been associated with increased hair regrowth, predominantly at the vertex (top of the head), in some individuals. It is most effective with a small amount of hair loss of recent onset. Cessation of treatment results in rapid return of hair loss. Side effects include hirsutism in women, fluid retention and cardiovascular symptoms. It has also been associated with increased hair loss in some individuals.
There are limited reports of improved hair regrowth whilst using minoxidil to treat telogen effluvium. However, if the underlying cause persists then discontinuing topical application will pre-empt return to pre-treatment levels of hair loss.
Finasteride is an anti-androgen medication, available as an oral treatment for androgenic alopecia in men only. In terms of effectiveness and indications for use, it is considered broadly equivalent to topical minoxidil. Side effects include loss of libido, erectile dysfunction and increased risk of male breast cancer. It is not suitable for treatment of other forms of hair loss.
Surgical and Prosthetic Options
In some cases of persistent hair loss, surgical interventions such as hair transplants or scalp reduction may be appropriate. They are not generally indicated for diffuse hair loss, as typifies telogen effluvium, and it is advisable to wait for at least two years following bariatric surgery before considering a hair transplant to allow time for hair growth to stabilize after rapid weight loss.
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