Hair Loss of Chemical Origin
Hair loss can result from the use of many chemicals frequently in therapeutic use, though the hair loss is usually diffuse.
Hair loss due to thallium:
Thallium salts were once used to remove hair from scalps that were infected with ringworm. The chemical causes hair loss by disrupting keratinisation, which is the process by which proteins called keratin form your hair. It becomes absorbed into the hair follicle during the growing, or anagen, stage of hair growth. Many of these hairs break within the follicle. An irregularity of the dark keratogenous zone and air bubbles within the shaft near the tapered tip give a distinctive appearance. Many other hairs, meanwhile, enter the catagen phase of the hair cycle, where the hair stops growing, prematurely.
After about 10 days of diffuse shedding of abnormal anagen hairs. The hair loss may rapidly become complete, or with lower doses of thallium, the initial diffuse hair loss may be followed by a gradual shedding of club hairs over a period of 3 to 4 months.
Hair loss due to thyroid antagonists:
A patient may develop diffuse hair loss when give anti-thyroid drugs to combat hyperthyroidism (overactive thyroid gland), converting the condition into hypothyroidism (underactive thyroid gland), which is known to cause diffuse hair loss.
Hair loss due to anticoagulants:
All anticoagulants, also known as blood thinners, will induce hair loss. The highest dose, not the duration of exposure, determines the degree of hair loss. Normal club hairs, which are non-growing hairs formed during the transitional stage between the growing and resting stages of hair growth, have been known to fall out 2 to 3 months after the blood thinners have achieved the effective blood level. A full recovery should follow slowly after the drug is stopped.
Hair loss due to cytostatic agents:
Many cytostatic drugs cause hair loss. A cytostatic drug is one that inhibits cell growth. Included with these are the drugs used to treat cancer, the most common of which is chemotherapy.
Hair loss due to an excess of vitamin A:
Both a deficiency and an excess of vitamin A can result in hair loss, specifically a slowly progressive thinning of the scalp and body hairs, eyebrows and eyelashes. An excess of vitamin A also leads to other symptoms, including dryness, irritability and sometimes pigmentation of the skin. Also, weight loss, fatigue, anaemia and bone pain are frequent and the liver and spleen are sometimes enlarged.
Hair loss due to boric acid:
Boric acid, also known generically as borax or chemically as sodium borate, is used in a variety of products, including detergents, water softeners, pesticides, soaps, disinfectants, enamel glazes, glass and hand-cleaner for industrial workers. It is also used as a food additive in some countries, making an appearance in French and Iranian caviar, for instance. Occupational exposure to this substance has caused diffuse hair loss.
These are just some of the many chemicals, or drugs, that can cause hair loss.