What is histamine and what does it do?
Histamine plays a crucial role in the immune response and acts as a neurotransmitter. A neurotransmitter is a chemical messenger that transmits signals between neurons (nerve cells) or from neurons to other target cells, such as muscle cells or gland cells.
It’s released during immune responses, particularly in allergic reactions. It causes blood vessels to widen, leading to increased blood flow to the affected area. This can result in symptoms such as redness, swelling, and itching (inflammation).
How scarring causes hair loss
Inflammation can contribute to hair loss through a condition called “cicatricial alopecia” or scarring alopecia. This type of hair loss occurs when inflammation damages and scars the hair follicles, preventing them from producing new hair.
Scarring alopecia is reportedly relatively uncommon compared to other types of hair loss. It accounts for about 3% to 7% of all hair loss cases seen in dermatology clinics. Unlike more common forms of hair loss, such as androgenetic alopecia (male and female pattern baldness), scarring alopecia involves the destruction of hair follicles, leading to permanent hair loss. However, I suspect other types of hair loss, like androgenic alopecia lead to scalp inflammation and scarring.
Research shows bald and balding scalps contain a greater number of inflammatory cytokines
Research has indicated that inflammatory cytokines are found in higher numbers in bald and balding scalps. Inflammatory cytokines are signaling molecules that play a role in inflammation and immune responses. Studies have shown that these cytokines are involved in the pathogenesis of hair loss conditions, including androgenetic alopecia (AGA) and scarring alopecia.
Key Research Findings on Inflammatory Cytokines in Balding Scalps
Inflammatory Cytokines and Androgenetic Alopecia (AGA)
A study published in the Journal of Investigative Dermatology found that increased levels of inflammatory cytokines, such as interleukin-1 (IL-1), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6), were present in the scalps of patients with androgenetic alopecia. These cytokines are known to contribute to inflammation and have been shown to impact the hair follicle’s normal growth cycle. Elevated cytokine levels can induce a shift from the anagen (growth) phase to the telogen (resting) phase, leading to hair thinning and loss.
Another study in the Journal of the American Academy of Dermatology also demonstrated that miniaturized hair follicles in balding scalps exhibited increased expression of inflammatory cytokines and chemokines. The study suggested that this inflammatory milieu might contribute to the progressive miniaturization of hair follicles seen in AGA.
Scarring Alopecia and Inflammatory Cytokines
In scarring alopecia, the inflammation is more intense and leads to the destruction of hair follicles. Research published in the British Journal of Dermatology highlighted that inflammatory cytokines, particularly IL-1 and TNF-α, were elevated in patients with scarring alopecia, such as lichen planopilaris and frontal fibrosing alopecia. The study showed that these cytokines contribute to the inflammatory process that destroys hair follicles, leading to irreversible hair loss.
Further research has indicated that Th1 and Th17 cytokine profiles, associated with certain immune responses, are elevated in scarring alopecia. These findings suggest that autoimmune mechanisms might be involved, where the body’s immune system mistakenly attacks hair follicles.
What you can do
Cytokine Modulation as a Potential Treatment Approach
The role of cytokines in hair loss has prompted research into treatments that target inflammatory pathways. For example, some studies have investigated the use of anti-inflammatory medications, such as corticosteroids and JAK inhibitors, to reduce inflammation and cytokine levels in the scalp. These treatments aim to prevent further hair loss by modulating the immune response and decreasing the production of harmful cytokines.
Topical anti-histamines as a hair loss treatment
Topical antihistamines have been explored as a potential treatment for hair loss, particularly because of their ability to reduce inflammation and modulate immune responses in the scalp. While there isn’t a large body of evidence specifically supporting the use of topical antihistamines to increase hair growth, some studies and clinical observations suggest they may help in certain cases of hair loss where inflammation and allergic reactions are contributing factors.
How Topical Antihistamines Might Help with Hair Loss
Reduction of Inflammation
Antihistamines work by blocking the action of histamines, which are compounds involved in allergic reactions and inflammation. Histamines can contribute to inflammation in the scalp, potentially damaging hair follicles and disrupting the hair growth cycle.
In cases of hair loss associated with inflammatory conditions (e.g., allergic contact dermatitis or some forms of scarring alopecia), reducing inflammation with antihistamines could theoretically help to protect hair follicles from damage and maintain their normal function.
Modulation of Immune Response
Hair loss conditions like alopecia areata (an autoimmune condition where the immune system attacks hair follicles) involve dysregulation of the immune response. Some studies have suggested that antihistamines, particularly those with immunomodulatory effects, could potentially help to balance the immune response and prevent hair loss in these cases.
Read next
Whats the best shampoo for hair loss? Certain antihistamines, like cetirizine, have shown some potential in reducing inflammatory cytokine release and T-cell activation, which might help reduce inflammation in the scalp and promote a healthier environment for hair growth.
Research and Evidence
Cetirizine Study
A study published in the Journal of Dermatological Treatment explored the effect of topical cetirizine (a second-generation antihistamine) on hair growth in patients with androgenetic alopecia (AGA). The study found that applying topical cetirizine resulted in a modest increase in hair density and hair growth over 6 months compared to a placebo. The authors suggested that cetirizine’s anti-inflammatory properties might contribute to this effect by reducing micro-inflammation around hair follicles, a known factor in AGA.
Case Reports and Anecdotal Evidence
There are some anecdotal reports and case studies suggesting that patients with hair loss due to scalp inflammation or allergic reactions have experienced improvement when treated with topical antihistamines. However, these cases are not enough to establish a standard treatment protocol or widespread efficacy.
