Atopic dermatitis

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Atopic dermatitis
Classification and external resources
Atopic dermatitis child.JPG
Atopic dermatitis
ICD-10L20
ICD-9691.8
OMIM603165
MedlinePlus000853
eMedicineemerg/130 derm/38 ped/2567 oph/479
MeSHD003876
 
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Atopic dermatitis
Classification and external resources
Atopic dermatitis child.JPG
Atopic dermatitis
ICD-10L20
ICD-9691.8
OMIM603165
MedlinePlus000853
eMedicineemerg/130 derm/38 ped/2567 oph/479
MeSHD003876

Atopic dermatitis (AD) also known as atopic eczema or eczema[1] is a type of dermatitis, an inflammatory, relapsing, non-contagious and itchy skin disorder.[2] It is often chronic in nature.[3] In children under one year of age usually the much of the body may be affected.[3] As they get older the back of the knees and front of the elbows are the most common area for the rash.[3] In adults the hands and feet are most affected.[3]

The cause is believed to involve a number of factors including: genetics, environmental exposures, and difficulties with the permeability of the skin.[3] The diagnosis is based on the signs and symptoms.[3] Other diseases that need to be excluded are contact dermatitis, psoriasis and seborrheic dermatitis.[3]

Treatment involves: avoiding things that make it worse, daily bathing with use of a moisturising cream afterwards, steroid creams when flairs occur, and medications to help with itchiness.[3] Antibiotics (either by mouth or topically) may be needed if infections develop.[3]

It affects more than 10% of children in the United States and is more common in younger children.[3] Most people outgrow it.[3] It has been given names like "prurigo Besnier," "neurodermatitis," "endogenous eczema," "flexural eczema," "infantile eczema," and "prurigo diathésique".[4]

Signs and symptoms[edit]

Atopic dermatitis of the anterior flextural crease of the elbow.
Pattern of atopic eczema varies with age

People with AD often have dry and scaly skin that spans the entire body, except perhaps the diaper area, and intensely itchy red, splotchy, raised lesions to form in the bends of the arms or legs, face, and neck.[5][6][7][8][9] These lesions then weep, crack, swell, and crust over.[9] These lesions are at a heightened risk for bacterial, fungal, or viral colonisation.[9]

Cause[edit]

The cause of AD is not known, although there is some evidence of genetic factors, and some evidence that growing up in a sanitary environment encourages AD.[6]

It seems to have a genetic component. Many people with AD have a family history of atopy. Atopy is an immediate-onset allergic reaction such as asthma, food allergies, AD or hay fever.[5][6] In 2006 it was discovered that mutations in the gene for the production of filaggrin strongly increased the risk for developing atopic dermatitis. Most importantly two mutations were found that affect approximately 5% of people in Western Europe that may disrupt the production of filaggrin. Filaggrin is a protein that plays an important role in the retention of water in the stratum corneum. People who have these mutations often have dry skin.[10] Filaggrin also plays an important role in keeping the skin surface slightly acidic, hence giving it anti-microbial effects. It is broken down into trans-urocanic acid which keeps the pH low.[11]

According to the hygiene hypothesis, when children are brought up exposed to allergens in the environment at a young age, their immune system is more likely to tolerate them, while children brought up in a modern "sanitary" environment are less likely to be exposed to those allergens at a young age, and, when they are finally exposed, develop allergies. There is some support for this hypothesis with respect to AD.

Those exposed to dogs while growing up have a lower risk of atopic dermatitis.[12] There is also support from epidemiological studies for a protective role for helminths against AD.[13] Likewise children with poor hygiene are at a lower risk for developing AD, as are children who drink unpasteurised milk.[13] Exposure to dust mites are believed to contribute to one's risk of developing AD.[14]

A diet high in fruits seems to have a protective effect against AD, whereas the opposite seems to be true for fast foods.[13]

The atopy patch test, which has been recognized as a useful diagnostic tool, involves the application of intact protein allergens in a patch test setting with an evaluation of the induced skin lesions after 24 to 72 hours, in an effort to determine if a specific allergen is causing the symptoms.[15][16]

Treatments[edit]

There is no known cure for AD, although treatments may reduce the severity and frequency of flares.[5] Applying moisturisers may prevent the skin from drying out and decrease the need for other medications.[17] Affected persons often report that improvement of skin hydration parallels with improvement in AD symptoms.[5] Additionally topical corticosteroids, especially hydrocortisone have proven themselves effective in managing AD.[5][6] If topical corticosteroids and moisturisers fail, short-term treatment with topical calcineurin inhibitors like tacrolimus or pimecrolimus may be tried, although they are usually avoided as they can cause skin cancer or lymphoma.[5] Alternatively systemic immunosuppressants may be tried such as ciclosporin, methotrexate, interferon gamma-1b, mycophenolate mofetil and azathioprine.[5][18] Antidepressants and naltrexone may be used to control pruritus (itchiness).[19]

A more novel form of treatment involves exposure to broad or narrow-band ultraviolet light. UV radiation exposure has been found to have a localized immunomodulatory effect on affected tissues and may be used to decrease the severity and frequency of flares.[20][21] In particular, Meduri et al. have suggested that the usage of UVA1 is more effective in treating acute flares, whereas narrow-band UVB is more effective in long-term management scenarios.[22] However, UV radiation has also been implicated in various types of skin cancer, and thus UV treatment is not without risk.[23] Vitamin D has also proven itself an effective treatment for AD.[24]

It is often recommended that persons with AD bathe regularly in lukewarm baths, especially in salt water, in order to moisten their skin.[6][25] Avoiding woollen clothing is usually recommended for those with AD, likewise silk, silver-coated clothing is often recommended as a therapeutic measure against AD.[25] Dilute bleach baths have also been reported effective at managing AD.[25]

Epidemiology[edit]

Since the beginning of the twentieth century, many mucosal inflammatory disorders have become more common; atopic eczema (AE) is a classic example of such a disease. It now affects 15–30% of children and 2–10% of adults in developed countries and in the United States has nearly tripled in the past thirty to forty years.[6][26]

See also[edit]

References[edit]

  1. ^ Williams, Hywel (2009). Evidence-Based Dermatology. John Wiley & Sons. p. 128. ISBN 9781444300178. 
  2. ^ De Benedetto, A; Agnihothri, R; McGirt, LY; Bankova, LG; Beck, LA (2009). "Atopic dermatitis: a disease caused by innate immune defects?". The Journal of investigative dermatology 129 (1): 14–30. doi:10.1038/jid.2008.259. PMID 19078985. 
  3. ^ a b c d e f g h i j k Tollefson, MM; Bruckner, AL; SECTION ON, DERMATOLOGY; SECTION ON, DERMATOLOGY (December 2014). "Atopic dermatitis: skin-directed management.". Pediatrics 134 (6): e1735–44. PMID 25422009. 
  4. ^ Abels, C; Proksch, E (2006). "Therapy of atopic dermatitis". Der Hautarzt; Zeitschrift fur Dermatologie, Venerologie, und verwandte Gebiete 57 (8): 711–725. doi:10.1007/s00105-006-1176-x. PMID 16816954. 
  5. ^ a b c d e f g Berke, R; Singh, A; Guralnick, M (July 2012). "Atopic dermatitis: an overview" (PDF). American Family Physician 86 (1): 35–42. PMID 22962911. 
  6. ^ a b c d e f Kim, BS (21 January 2014). Fritsch, P; Vinson, RP; Perry, V; Quirk, CM; James, WD, ed. "Atopic Dermatitis". Medscape Reference. WebMD. Retrieved 3 March 2014. 
  7. ^ Brehler, R (2009). "Atopic Dermatitis". In Lang, F. Encyclopedia of molecular mechanisms of diseases. Berlin: Springer. ISBN 978-3-540-67136-7. 
  8. ^ Baron, SE; Cohen, SN; Archer, CB (May 2012). "Guidance on the diagnosis and clinical management of atopic eczema" (PDF). Clinical and Experimental Dermatology 37: 7–12. doi:10.1111/j.1365-2230.2012.04336.x. PMID 22486763. 
  9. ^ a b c Schmitt, J; Langan, S; Deckert, S; Svensson, A; von Kobyletzki, L; Thomas, K; Spuls, P; Harmonising Outcome Measures for Atopic Dermatitis (HOME), Initiative (December 2013). "Assessment of clinical signs of atopic dermatitis: a systematic review and recommendation.". The Journal of Allergy and Clinical Immunology 132 (6): 1337–47. doi:10.1016/j.jaci.2013.07.008. PMID 24035157. 
  10. ^ Palmer, CN; Irvine, AD; Terron-Kwiatkowski, A; Zhao, Y; Liao, H; Lee, SP; Goudie, DR; Sandilands, A; Campbell, LE; Smith, FJ; O'Regan, GM; Watson, RM; Cecil, JE; Bale, SJ; Compton, JG; DiGiovanna, JJ; Fleckman, P; Lewis-Jones, S; Arseculeratne, G; Sergeant, A; Munro, CS; El Houate, B; McElreavey, K; Halkjaer, LB; Bisgaard, H; Mukhopadhyay, S; McLean, WH (April 2006). "Common loss-of-function variants of the epidermal barrier protein filaggrin are a major predisposing factor for atopic dermatitis.". Nature Genetics 38 (4): 441–6. doi:10.1038/ng1767. PMID 16550169. 
  11. ^ Jungersted JM, Scheer H, Mempel M, et al. Stratum corneum lipids, skin barrier function and filaggrin mutations in patients with atopic eczema. Allergy. 2010;65:911–918.
  12. ^ Pelucchi, C; Galeone, C; Bach, JF; La Vecchia, C; Chatenoud, L (September 2013). "Pet exposure and risk of atopic dermatitis at the pediatric age: a meta-analysis of birth cohort studies.". The Journal of Allergy and Clinical Immunology 132 (3): 616–622.e7. doi:10.1016/j.jaci.2013.04.009. PMID 23711545. 
  13. ^ a b c Flohr, C; Mann, J (January 2014). "New insights into the epidemiology of childhood atopic dermatitis" (PDF). Allergy 69 (1): 3–16. doi:10.1111/all.12270. 
  14. ^ Fuiano, N; Incorvaia, C (June 2012). "Dissecting the causes of atopic dermatitis in children: less foods, more mites." (PDF). Allergology International 61 (2): 231–43. doi:10.2332/allergolint.11-RA-0371. PMID 22361514. 
  15. ^ "Lessons from atopy patch testing in ... [Curr Allergy Asthma Rep. 2004]". Ncbi.nlm.nih.gov. 2014-01-24. Retrieved 2014-04-09. 
  16. ^ "Role and Significance of Atopy Patch Test". Retrieved 2014-04-09. 
  17. ^ Varothai, S; Nitayavardhana, S; Kulthanan, K (Jun 2013). "Moisturizers for patients with atopic dermatitis." (PDF). Asian Pacific Journal of Allergy and Immunology 31 (2): 91–8. PMID 23859407. 
  18. ^ Yarbrough, KB; Neuhaus, KJ; Simpson, EL (March–April 2013). "The effects of treatment on itch in atopic dermatitis". Dermatologic Therapy 26 (2): 110–119. doi:10.1111/dth.12032. PMID 23551368. 
  19. ^ Kim, K (Nov 2012). "Neuroimmunological Mechanism of Pruritus in Atopic Dermatitis Focused on the Role of Serotonin." (PDF). Biomolecules & therapeutics 20 (6): 506–512. doi:10.4062/biomolther.2012.20.6.506. PMC 3762292. PMID 24009842. 
  20. ^ Tintle, S; Shemer, A; Suárez-Fariñas, M; Fujita, H; Gilleaudeau, P; Sullivan-Whalen, M; Johnson-Huang, L; Chiricozzi, A; Cardinale, I; Duan, S; Bowcock, A; Krueger, J. G.; Guttman-Yassky, E (2011). "Reversal of atopic dermatitis with narrow-band UVB phototherapy and biomarkers for therapeutic response". Journal of Allergy and Clinical Immunology 128 (3): 583–93.e1–4. doi:10.1016/j.jaci.2011.05.042. PMC 3448950. PMID 21762976.  edit
  21. ^ Beattie, P.E.; Finlan, L.E.; Kernohan, N.M.; Thomson, G.; Hupp, T.R.; Ibbotson, S.H. (2005). "The effect of ultraviolet (UV) A1, UVB and solar-simulated radiation on p53 activation and p21Waf1/Cip1". British Journal of Dermatology 152 (5): 1001–1008. doi:10.1111/j.1365-2133.2005.06557.x. PMID 15888160. 
  22. ^ Meduri, NB; Vandergriff, T; Rasmussen, H; Jacobe, H (2007). "Phototherapy in the management of atopic dermatitis: a systematic review". Photodermatology, Photoimmunology & Photomedicine 23 (4): 106–112. doi:10.1111/j.1600-0781.2007.00291.x. PMID 17598862. 
  23. ^ Jans, J; Garinis, GA; Schul, W; Van Oudenaren, A; Moorhouse, M; Smid, M; Sert, YG; Van Der Velde, A; Rijksen, Y; De Gruijl, FR; Van Der Spek, PJ; Yasui, A; Hoeijmakers, JHJ; Leenen, PJM; Van Der Horst, GTJ (2006). "Differential Role of Basal Keratinocytes in UV-Induced Immunosuppression and Skin Cancer". Molecular and Cellular Biology 26 (22): 8515–8526. doi:10.1128/MCB.00807-06. PMC 1636796. PMID 16966369. 
  24. ^ Samochocki, Z; Bogaczewicz, J; Jeziorkowska, R; Sysa-Jędrzejowska, A; Glińska, O; Karczmarewicz, E; McCauliffe, DP; Woźniacka, A (August 2013). "Vitamin D effects in atopic dermatitis.". Journal of the American Academy of Dermatology 69 (2): 238–44. doi:10.1016/j.jaad.2013.03.014. PMID 23643343. 
  25. ^ a b c Lio, PA (October 2013). "Non-pharmacologic therapies for atopic dermatitis". Current Allergy and Asthma Reports 13 (5): 528–538. doi:10.1007/s11882-013-0371-y. PMID 23881511. 
  26. ^ Saito, Hirohisa (2005). "Much Atopy about the Skin: Genome-Wide Molecular Analysis of Atopic Eczema". International Archives of Allergy and Immunology 137 (4): 319–325. doi:10.1159/000086464. PMID 15970641. 

External links[edit]