What Is Alopecia?
Alopecia areata is an autoimmune disease that occurs when the immune system attacks the hair follicles and leads to hair loss. Alopecia usually affects the head and face. The amount of hair fall differs for each individual, but hair fall often occurs in clumps. Hair falls usually occurs in small, round patches the size of a quarter, but in some cases, hair loss is more extensive. The hair grows back for falls out for some people, whereas, in others, hair grows back for good. Most people with this disease are physically healthy with the absence of other symptoms.
The course of alopecia varies from individual to individual. Some experience one episode of hair loss, while others have bouts of hair fall throughout their lives. The recovery from hair fall is also unpredictable, with hair regrowing in some individuals but not others. There is no permanent cure for alopecia, but treatments are available for hair to grow back more quickly. There are different types of alopecia:
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Alopecia Areata Totalis - Complete hair on the head.
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Alopecia Areata Universalis - Hair loss over the entire body.
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Diffuse Alopecia Areata - Sudden thinning of the hair and not in patches.
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Ophiasis Alopecia Areata - Hair loss is seen in a band shape around the back and sides of the head.
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Patchy Alopecia Areata - Hair loss occurs in coin-sized patches on the head or other parts of the body.
What Are the Symptoms of Alopecia?
The main and mostly the only symptom of alopecia is hair loss. Hair loss often occurs in patches on the scalp, and these patches become bigger and grow together into a bald spot. These patches often measure several centimeters or less. Hair loss can occur in any part of the body, like the beard, eyebrows, eyelashes, etc. Also, hair loss can occur in a specific area or in multiple spots.
Initially, hair fall gets noticed because of excess clumps of hair on the pillow or during the shower. In rare cases, extensive hair loss can occur, which can indicate another type of alopecia, like alopecia totalis or alopecia universalis. Hair may grow back and then may fall out again in most cases. The extent of hair fall and regrowth varies from person to person. Excess hair loss can be noted during winter. Other than the hair, the finger, and toenails become brittle, red, and pitted for some individuals.
What Are the Toxic Agents That Cause Alopecia?
Following are some of the agents that can result in alopecia
Thallium
Thallium is a heavy metal, and it is colorless, odorless, tasteless, and dissolves in liquids completely. These properties make thallium the best thing for criminal poisoning. The lethal dose for thallium sulfate is 10 to 15 mg/kg. Thallium poisoning causes malfunction of peripheral nerves and gastrointestinal symptoms such as nausea, vomiting, and diarrhea. Thallium poisoning can be accidental (occupational exposure like certain alloys, electronics, and semiconductor materials) and intentional (malicious or suicidal) poisoning manufacture of certain electronics, semiconductor materials, and alloys.
Thallium exposure can cause hair fall by binding to the sulphydryl group present in the hair keratins and affecting the formation of the hair shaft. Thallium poisoning can lead to nonscarring alopecia (active hair loss) over two to four weeks. Only in rare cases, hair loss may occur for a shorter time course.
Mercury
Mercury is also a heavy metal; similar to thallium, mercury binds to the sulphydryl group of hair keratins and can result in anagen effluvium. Mercury toxicity can cause free-radical damage and lead to symptoms like fatigue, irritability, memory loss, depression, insomnia, recurrent infections, hair loss, and tremors.
Boric Acid
Boric acid is the weak acid of boron. It is found widely in nature and commonly used by the glass, enamel, and metal industries. Boric acid is also found in food preservatives, antiseptics, flame retardants, and insecticides. Boric acid toxicity can cause symptoms like causes fever, altered mental status, bilateral palmar erythema, diffuse erythematous skin eruption, and stiffness. It can also cause hair loss and eyelash loss.
Arsenic
Arsenic occurs naturally in soil, water, and seafood. It is used in industries to make animal feed additives, metal alloys, and pesticides. The association between alopecia and arsenic needs to be better understood. A study reported that about 8 out of 73 individuals in West Bengal have alopecia due to consuming water containing arsenic. High arsenic in water also causes symptoms like skin and mucosal lesions and hepatomegaly. Potentially toxic levels of arsenic are reported in seaweed. Cases have been reported with alopecia, weight loss, nail changes, scaly erythematous skin, and weakness due to a diet consisting of excess arsenic, mainly from seaweed soup.
Selenium
Selenium toxicity resembles that of heavy metal poisoning, like hair loss and Mees' lines (white bands of line that appear on the fingernails or toenails). Other symptoms of selenium toxicity include diarrhea, nausea, vomiting, and progression to neurological problems like paralysis and unsteady gait. A theory suggests that selenium poisoning occurs due to selenium substituting sulfur in hair keratin proteins, leading to abnormal development of hair and nail protein structure and loss of disulfide bridges. Selenium is found in high concentrations in paradise nuts as seleno-cystathionine. Due to its high concentration in paradise nut, hair loss cases have been reported after consuming more than one hand full of the nut.
Podostroma Cornu-Damae
Podostroma cornu-damae is a highly toxic fungus species seen rarely in the Hypocreaceae family. The mechanism of toxin acts is unclear, but several death has been reported in Japan due to this fungus. Ingestion of the fungi has caused alopecia and other symptoms like fever, weakness, desquamation of hands and feet, abdominal discomfort, and neutropenia.
Hypervitaminosis A
Vitamin A is required for vision, skin health, and immune system enhancement. Vitamin A is obtained in the diet in two forms that are retinol and carotenoids. Vitamin A toxicity is related to ingesting high quantities of the retinol form, which causes alopecia, eyelash and eyebrows hair loss, weight loss, fatigue, malaise, flaky skin, and nail dystrophy.
Botulinum Toxin Type A
Botulinum A injections have been used for a long time without knowing their connection with alopecia. Recently, facial alopecia and unilateral madarosis have been reported due to the long-term use of botulinum A injections.
MT-45
MT-45 is a synthetic opioid originally developed as an opioid analgesic comparable to Morphine. MT-45 has also been reported to cause hair loss. Other symptoms include hair depigmentation, folliculitis, elevated liver enzymes, Mees' lines, dermatitis, and dry eyes.
Conclusion
Alopecia areata is an autoimmune disease that affects the hair follicles and leads to hair loss. There is no permanent cure for alopecia. The mechanism that causes alopecia is also not clear. Many agents like thallium, mercury, selenium, boric acid, vitamin A, botulinum toxin, fungal species P. cornu-damae, and MT-45 are reported to cause hair loss. However, there is less evidence to support this. Research is being conducted to learn more about the mechanism, treatment, and prevention of hair loss.
