Monobenzone
Encyclopedia
Monobenzone is a compound used as a topical
drug
for medical depigmentation
.
of hydroquinone
. Monobenzone occurs as a white, almost tasteless crystalline powder, soluble in alcohol
and practically insoluble in water
.
from melanocytes. The same action is thought to be responsible for the depigmenting effect of the drug in humans. Monobenzone may cause destruction of melanocytes and permanent depigmentation.
The histology
of the skin after depigmentation with topical monobenzone is the same as that seen in vitiligo
; the epidermis is normal except for the absence of identifiable melanocytes. Therefore, monobenzone is used as a topical medicine to permanently depigment normal skin surrounding vitiliginous lesions only in patients with disseminated (greater than 50 percent of body surface area) idiopathic
vitiligo.
There is no known cure for the disease but treatments do exist. Some patients use cosmetic make-up to cover the white spots, while others use treatments such as repigmentation through a series of ultraviolet light treatments and surgical transplant of melanocytes. In severe cases, when over fifty percent of the body surface area is covered with white patches, patients cannot use these repigmentation treatments. They can, however, choose to eliminate the skin colour from the normal areas using monobenzone cream, a process called depigmentation. This gives the patient’s skin a permanent, even, pale white colour. Since the application of monobenzone is topical, it can be done in the privacy of one’s home. It is simple to do and does not require frequent visits to a doctor’s office. Twice daily monobenzone topical cream must be applied.
The major side effect of depigmentation therapy is inflammation (redness and swelling) of the skin. Patients may experience itching or dry skin. The process of depigmentation is gradual. The length of time using monobenzone topical cream ranges from four months to a year. The patient must understand the concept of continued existence of a source of follicular melanocytes and that exposure to the sun can lead to perifollicular pigmented macules. Rigorous limitation of sun exposure is essential following depigmentation therapy, not only to avoid burns, but to avoid perifollicular repigmentation. Wearing high-SPF sunscreens is the ultimate physical barrier to help avoid burns and repigmentation.
There are at least three theories about the principal cause of vitiligo:
Topical
In medicine, a topical medication is applied to body surfaces such as the skin or mucous membranes such as the vagina, anus, throat, eyes and ears.Many topical medications are epicutaneous, meaning that they are applied directly to the skin...
drug
Drug
A drug, broadly speaking, is any substance that, when absorbed into the body of a living organism, alters normal bodily function. There is no single, precise definition, as there are different meanings in drug control law, government regulations, medicine, and colloquial usage.In pharmacology, a...
for medical depigmentation
Depigmentation
Depigmentation is the lightening of the skin, or loss of pigment. Depigmentation of the skin can be caused by a number of local and systemic conditions. The pigment loss can be partial or complete...
.
Chemistry
Monobenzone is the monobenzyl etherEther
Ethers are a class of organic compounds that contain an ether group — an oxygen atom connected to two alkyl or aryl groups — of general formula R–O–R'. A typical example is the solvent and anesthetic diethyl ether, commonly referred to simply as "ether"...
of hydroquinone
Hydroquinone
Hydroquinone, also benzene-1,4-diol or quinol, is an aromatic organic compound that is a type of phenol, having the chemical formula C6H42. Its chemical structure, shown in the table at right, has two hydroxyl groups bonded to a benzene ring in a para position. It is a white granular solid...
. Monobenzone occurs as a white, almost tasteless crystalline powder, soluble in alcohol
Ethanol
Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
and practically insoluble in water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
.
Pharmacology
The topical application of monobenzone in animals decreases the excretion of melaninMelanin
Melanin is a pigment that is ubiquitous in nature, being found in most organisms . In animals melanin pigments are derivatives of the amino acid tyrosine. The most common form of biological melanin is eumelanin, a brown-black polymer of dihydroxyindole carboxylic acids, and their reduced forms...
from melanocytes. The same action is thought to be responsible for the depigmenting effect of the drug in humans. Monobenzone may cause destruction of melanocytes and permanent depigmentation.
The histology
Histology
Histology is the study of the microscopic anatomy of cells and tissues of plants and animals. It is performed by examining cells and tissues commonly by sectioning and staining; followed by examination under a light microscope or electron microscope...
of the skin after depigmentation with topical monobenzone is the same as that seen in vitiligo
Vitiligo
Vitiligo is a condition that causes depigmentation of sections of skin. It occurs when melanocytes, the cells responsible for skin pigmentation, die or are unable to function. The cause of vitiligo is unknown, but research suggests that it may arise from autoimmune, genetic, oxidative stress,...
; the epidermis is normal except for the absence of identifiable melanocytes. Therefore, monobenzone is used as a topical medicine to permanently depigment normal skin surrounding vitiliginous lesions only in patients with disseminated (greater than 50 percent of body surface area) idiopathic
Idiopathic
Idiopathic is an adjective used primarily in medicine meaning arising spontaneously or from an obscure or unknown cause. From Greek ἴδιος, idios + πάθος, pathos , it means approximately "a disease of its own kind". It is technically a term from nosology, the classification of disease...
vitiligo.
Vitiligo
Vitiligo is a chronic skin disease that causes loss of melanocytes which are pigment-producing cells, resulting in irregular pale or white patches of skin. The cellular and molecular mechanisms leading to the destruction of melanocytes in this disorder have not yet been detected. Vitiligo affects approximately 0.5 to 1 percent of the population. Individuals of all ethnic origins and both sexes can be affected; however, it is much more noticeable on darker skin. Common areas of the skin losing pigment are the face, lips, hands, arms, legs, and genital areas. Patches of the epidermis affected by vitiligo often occur symmetrically across both sides on the body. Seldom, small areas of the body may repigment as they are recolonised by melanocytes.There is no known cure for the disease but treatments do exist. Some patients use cosmetic make-up to cover the white spots, while others use treatments such as repigmentation through a series of ultraviolet light treatments and surgical transplant of melanocytes. In severe cases, when over fifty percent of the body surface area is covered with white patches, patients cannot use these repigmentation treatments. They can, however, choose to eliminate the skin colour from the normal areas using monobenzone cream, a process called depigmentation. This gives the patient’s skin a permanent, even, pale white colour. Since the application of monobenzone is topical, it can be done in the privacy of one’s home. It is simple to do and does not require frequent visits to a doctor’s office. Twice daily monobenzone topical cream must be applied.
The major side effect of depigmentation therapy is inflammation (redness and swelling) of the skin. Patients may experience itching or dry skin. The process of depigmentation is gradual. The length of time using monobenzone topical cream ranges from four months to a year. The patient must understand the concept of continued existence of a source of follicular melanocytes and that exposure to the sun can lead to perifollicular pigmented macules. Rigorous limitation of sun exposure is essential following depigmentation therapy, not only to avoid burns, but to avoid perifollicular repigmentation. Wearing high-SPF sunscreens is the ultimate physical barrier to help avoid burns and repigmentation.
There are at least three theories about the principal cause of vitiligo:
- Nerve endings in the skin release a chemical that is toxic to the melanocytes.
- Melanocytes simply self-destruct.
- It is a type of autoimmune disease in which the immune system targets the body's own cells and tissues.