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| [[Category:Autoimmune diseases]] | | [[Category:Autoimmune diseases]] |
| [[Category:Pigment disorders]] | | [[Category:Pigment disorders]] |
| | [[Category:Skin diseases]] |
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| [[ar:بهاق]] | | [[ar:بهاق]] |
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| {{WH}} | | {{WH}} |
| {{WS}} | | {{WS}} |
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| == Overview ==
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| '''Vitiligo''' ([[International Phonetic Alphabet|IPA]] {{IPA|/ˌvɪtəˈlaɪgo/}}) or '''leukoderma''' is a [[Chronic (medicine)|chronic skin condition]] that causes loss of [[Biological pigment|pigment]], resulting in irregular pale patches of [[skin]]. The precise [[etiology|cause]] of vitiligo is complex and not fully understood. There is some evidence suggesting it is caused by a combination of [[Autoimmunity|auto-immune]], [[Genetics|genetic]], and environmental factors. The population incidence in the United States is considered to be between 1% and 2%. It is considered a rare condition/rare disease that affects only 1 in 2,000 people.
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| According to Diseases Database:
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| "A disorder consisting of areas of macular depigmentation, commonly on extensor aspects of extremities, on the face or neck, and in skin folds. Age of onset is often in young adulthood and the condition tends to progress gradually with lesions enlarging and extending until a [[quiescent]] state is reached."
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| == Diagnosis ==
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| === Signs ===
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| Half of people with vitiligo develop patches of de-pigmented skin appearing on [[Limb|extremities]] before their 20s. The patches may grow, shrink, or remain constant in size. Patches often occur symmetrically across both sides on the body. Occasionally small areas may repigment as they are recolonised by melanocytes. The location of vitiligo affected skin changes over time, with some patches re-pigmenting and others becoming affected.
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| In some cases, mild [[Physical trauma|trauma]] to an area of skin seems to cause new patches - for example around the [[ankle]]s (caused by friction with shoes or sneakers). Vitiligo may also be caused by [[Stress (medicine)|stress]] that affects the [[immune system]], leading the body to react and start eliminating skin pigment.
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| Vitiligo on the [[scalp]] may affect the color of the [[hair]] (though not always), leaving white patches or streaks. It will similarly affect facial and body hair.
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| === Symptoms ===
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| The following list of symptoms mentioned from various sources includes the 23 mentioned below:
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| * Hand white patches
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| * Feet white patches
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| * Arm white patches
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| * Face white patches
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| * Lip white patches
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| * Armpit white patches
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| * Chest white patches
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| * Back white patches
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| * Shoulders white patches
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| * Groin white patches
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| * White patches around the mouth
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| * White patches around the eyes
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| * Nostril white patches
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| * Navel white patches
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| * Genital white patches
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| * Mucous membrane white patches
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| * Rectal white patches
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| * Uveitis
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| * Retina white patches
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| * Premature graying
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| * Gray scalp hair
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| * Gray eyelashes
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| * Gray eyebrows
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| * Gray beard
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| * Sun sensitivity
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| === Physical Examination ===
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| ====Skin====
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| [[Image:vitiligo.jpg|thumb|left|Vitiligo (pernicious anemia, DM, Addison's, Hypothyroid)<ref>http://picasaweb.google.com/mcmumbi/USMLEIIImages</ref>]]
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| {{clr}}
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| == Disease mechanism ==
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| Vitiligo is associated with autoimmune and inflammatory diseases, commonly thyroid overexpression and underexpression. Jin in the New England Journal of Medicine reported a study comparing 656 people with and without vitiligo in 114 families, which found several mutations (single-nucleotide polymorphisms) in the [[Pattern recognition receptor|NALP1]] gene.<ref>{{cite journal |author=Gregersen PK |title=Modern genetics, ancient defenses, and potential therapies |journal=N. Engl. J. Med. |volume=356 |issue=12 |pages=1263-6 |year=2007 |pmid=17377166 |doi=10.1056/NEJMe078017}}</ref><ref>{{cite journal |author=Jin Y, Mailloux CM, Gowan K, Riccardi SL, LaBerge G, Bennett DC, Fain PR, Spritz RA |title=NALP1 in vitiligo-associated multiple autoimmune disease |journal=N. Engl. J. Med. |volume=356 |issue=12 |pages=1216-25 |year=2007 |pmid=17377159 |doi=10.1056/NEJMoa061592}}</ref> The NALP1 gene, which is on chromosome 17 located at 17p13, is on a cascade that regulates inflammation and cell death, including myeloid and lymphoid cells, which are white cells that are part of the immune response. NALP1 is expressed at high levels in T cells and Langerhan's cells, white cells that are involved in skin autoimmunity.
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| Among the inflammatory products of NALP1 are caspase 1 and caspase 5, which activate the inflammatory cytokine interleukin-1β. Interleukin-1β is expressed at high levels in patients with vitiligo. There are compounds which inhibit caspase and interleukin-1β, and so might be useful drugs for vitiligo and associated autoimmune diseases.
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| Of the 656 people, 219 had vitiligo only, 70 had vitiligo with autoimmune thyroid disease, and 60 had vitiligo and other autoimmune diseases. Addison's disease (typically an autoimmune destruction of the adrenal glands) may cause vitiligo.
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| In one of the mutations, the amino acid leucine in the NALP1 protein was replaced by histidine (Leu155->His). The original protein and sequence is highly conserved in evolution, and found in humans, chimpanzee, [[Rhesus Macaque|rhesus monkey]], and bush baby, which means that it's an important protein and an alteration is likely to be harmful.
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| The following is the normal DNA and protein sequence in the NALP1 gene:
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| {| class="wikitable"
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| |-
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| |TCA
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| |CTC
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| |CTC
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| |TAC
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| |CAA
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| |-
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| |Ser
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| |Leu
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| |Leu
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| |Tyr
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| |Gln
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| |-
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| |S
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| |L
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| |L
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| |Y
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| |Q
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| |}
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| In some cases of vitiligo the first leucine is altered to histidine, by a Leu155→His mutation:
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| {| class="wikitable"
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| |-
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| |TCA
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| |C'''A'''C
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| |CTC
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| |TAC
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| |CAA
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| |-
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| |Ser
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| |'''His'''
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| |Leu
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| |Tyr
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| |Gln
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| |-
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| |S
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| |'''H'''
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| |L
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| |Y
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| |Q
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| |}
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| (Leucine is nonpolar and hydrophobic; histidine is positively charged and hydrophilic, so it is unlikely to serve the same function.<ref>[http://www.bio.davidson.edu/Courses/Molbio/aatable.html List of Amino Acids and Their Abbreviations]</ref>
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| <ref>[http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/Codons.html#The_DNA_Codons The Genetic Code (DNA)]</ref>)
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| The normal sequence of the DNA code for NALP1 of TCACTCCTCTACCAA is replaced in some of these vitiligo families by the sequence TCACACCTCTACCAA,<ref>[http://www.ensembl.org/Homo_sapiens/transview?transcript=ENST00000262467;db=core Ensembl Transcript Report Ensembl Transcript ID: NST00000262467]</ref> which respectively code for the amino acid sequence of the normal NALP1 protein SLLYQ being replaced by SHLYQ.<ref>[http://www.ensembl.org/Homo_sapiens/protview?db=core;peptide=ENSP00000262467 Ensembl Protein Report Ensembl Peptide: ID ENSP00000262467]</ref>
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| ==Psychological effects==
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| Vitiligo can have a significant effect on the [[Mental health|psychological well being]] of the [[patient]].<ref>{{cite journal |author=Mechri A, Amri M, Douarika AA, Ali Hichem BH, Zouari B, Zili J |title=[Psychiatric morbidity and quality of life in Vitiligo: a case controlled study] |language=French |journal=La Tunisie médicale |volume=84 |issue=10 |pages=632-5 |year=2006 |pmid=17193855 |doi=}}</ref> This is especially true for darker skinned patients as the contrast between pigmented and depigmented skin can be quite drastic.
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| In some cultures there is a [[Social stigma|stigma]] attached to having vitiligo. Those affected with the condition are sometimes thought to be evil or diseased and are sometimes shunned by others in the community. People with vitiligo may feel [[Depression (mood)|depressed]] because of this stigma or because their appearance has changed dramatically. Other people with vitiligo experience no negative psychological effects at all.
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| ==Treatment==
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| <!-- Unsourced image removed: [[Image:Girlwithvitiligo.jpg|thumb|left|Sharni Kaur, right, and her mother, Roop Singh. Sharni has had vitiligo, which causes her skin to lighten, since she was nine years old.]] -->
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| There are a number of ways to alter the appearance of vitiligo without addressing its underlying cause. In mild cases, vitiligo patches can be hidden with makeup or other cosmetic camouflage solutions. If the affected person is pale-skinned, the patches can be made less visible by avoiding [[sunlight]] and the [[sun tanning]] of unaffected skin. However, exposure to sunlight may also cause the melanocytes to regenerate to allow the pigmentation to come back to its original color.
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| The traditional treatment given by most dermatologists is [[corticosteroid]] cream.<ref>{{cite journal |author=Kwinter J, Pelletier J, Khambalia A, Pope E |title=High-potency steroid use in children with vitiligo: a retrospective study |journal=J. Am. Acad. Dermatol. |volume=56 |issue=2 |pages=236-41 |year=2007 |pmid=17224367 |doi=10.1016/j.jaad.2006.08.017}}</ref>
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| [[Phototherapy]] may also beneficial using exposure to long-wave [[ultraviolet]] (UVA) light from the sun or from UVA, together with [[Psoralen]], called "[[PUVA]]", Or with UVB Narrowband lamps (without Psoralen), can help in many cases. Psoralen can be taken in a pill 1-2 hours before the exposure or as a Psoralen soaking of the area 1/2 hour before the exposure. Lately, PUVA is being more and more replaced with exposure UVB Narrowband light at a wavelength of 311-313 nanometers. This treatment does not involve Psoralen since the effect of the lamp is strong enough. The source for the UVB Narrowband UVB light can be special fluorecent lamps that treat large area in few minutes, or high power fiber-optic devices in a fraction of a second.
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| Studies have also shown that [[immunomodulator]] creams such as [[Protopic]] and [[Elidel]] also cause repigmentation in some cases, when used with UVB Narrowband treatments.<ref>{{cite journal |author=Tanghetti EA |title=Tacrolimus ointment 0.1% produces repigmentation in patients with vitiligo: results of a prospective patient series |journal=Cutis; cutaneous medicine for the practitioner |volume=71 |issue=2 |pages=158-62 |year=2003 |pmid=12635898 |doi=}}</ref><ref>{{cite journal |author=Silverberg NB, Lin P, Travis L, Farley-Li J, Mancini AJ, Wagner AM, Chamlin SL, Paller AS |title=Tacrolimus ointment promotes repigmentation of vitiligo in children: a review of 57 cases |journal=J. Am. Acad. Dermatol. |volume=51 |issue=5 |pages=760-6 |year=2004 |pmid=15523355 |doi=10.1016/j.jaad.2004.05.036}}</ref>
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| Alternatively, some people with vitiligo opt for chemical depigmentation, which uses 20% monobenzylether of [[hydroquinone]]. This process is irreversible and generally ends up with complete or mostly complete depigmentation.
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| In late October of 2004, doctors successfully transplanted [[melanocyte]]s to vitiligo affected areas, effectively repigmenting the region. The procedure involved taking a thin layer of pigmented skin from the patient's [[Gluteal muscles|gluteal]] region. Melanocytes were then separated out and used to make a [[Cell (biology)|cellular]] suspension. The area to be treated was then [[Ablation|ablated]] with a [[laser|medical laser]], and the melanocyte [[Skin grafting|graft]] applied. Three weeks later, the area was exposed to UV light repeatedly for two months. Between 73 and 84 percent of patients experienced nearly complete repigmentation of their skin. The longevity of the repigmentation differed from person to person.<ref>{{cite journal |author=van Geel N, Ongenae K, De Mil M, Haeghen YV, Vervaet C, Naeyaert JM |title=Double-blind placebo-controlled study of autologous transplanted epidermal cell suspensions for repigmenting vitiligo |journal=Archives of dermatology |volume=140 |issue=10 |pages=1203-8 |year=2004 |pmid=15492182 |doi=10.1001/archderm.140.10.1203}}</ref>
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| In early 2008 scientists at King's College London, England, make a major breakthrough in treatment of Vitiligo. They discovered that piperine, a chemical derived from black pepper can aid repigmentaion in skin, especially when combined with pUVA therapy produces a longer lasting and more even pigmentation than previous treatments [http://news.bbc.co.uk/1/hi/health/7244474.stm].
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