Quimiotecnia Diagnóstico AB
Productos de prueba de parche de diagnóstico del fabricante líder mundial,
y suministrado exclusivamente en la Región del Caribe
por AllerDerm Caribe n Ltd
A continuación se muestran apartados de interés para el Paciente Alérgico
sobre dermatitis alérgica de contacto y sobre pruebas de parche.
LOS ESPECIALISTAS EN PRUEBAS DE PARCHE DEL CARIBE
¿QUÉ MÉDICO?
Información del paciente
En todo el mundo, la dermatitis alérgica de contacto puede ser diagnosticada por un médico de atención primaria o de familia, aunque lo más habitual es que dicho médico generalista haya recomendado que su paciente que padece dicha afección sea remitido a un especialista en dermatología o quizás en alergia. La razón es simplemente que existen diversas afecciones de la piel que se asemejan a la Dermatitis Alérgica de Contacto, y si la terapia sintomática prescrita por el médico generalista no logra resolver adecuadamente el malestar del paciente, entonces puede ser necesario un diagnóstico más preciso, incluyendo la identificación de la causa. causa y el origen del problema, de modo que se puedan implementar medidas para evitarlo.
En muchos casos clínicos, la aparente dermatitis alérgica de contacto puede no ser el único problema médico del paciente; por ejemplo, el paciente también podría ser alérgico a diversos alérgenos inhalados, como los ácaros del polvo doméstico o las esporas de polen. En tales casos, es posible que el paciente ya esté bajo el cuidado de un alergólogo especialista, quien luego puede intentar diagnosticar y tratar también una aparente dermatitis alérgica de contacto.
En muchos casos clínicos el paciente es menor de 18 años por lo que puede que ya esté bajo el cuidado de un Pediatra Especialista. Sin embargo, un pediatra normalmente derivaría al paciente a un colega dermatólogo para investigar la aparente dermatitis alérgica de contacto.
Ciertamente, en la región del Caribe, los casos de Dermatitis Alérgica de Contacto eventualmente serían atendidos por un Dermatólogo o un Alergólogo, o quizás un Internista.
Pero incluso entre los dermatólogos, no todos los dermatólogos participan en el diagnóstico y tratamiento de la ACD. Algunos dermatólogos se centran en los cánceres de piel; algunos dermatólogos se centran en la medicina estética, y quizás sólo uno de cada tres dermatólogos se centrará en la práctica clásica de la dermatología que incluye pruebas de parche para identificar sustancias problemáticas que causan dermatitis alérgica de contacto.
Entonces, si usted como Paciente cree que puede estar sufriendo una Dermatitis Alérgica de Contacto debido a una sustancia que se encuentra en su lugar de trabajo (un hapteno ocupacional) o a algún elemento de su vida personal, entonces no sufra innecesariamente...
- Pídale consejo a su farmacéutico minorista y tratamientos de venta libre para mejorar sus síntomas...
- Consulte a su médico de atención primaria por tratamientos más potentes para mejorar sus síntomas...
- Solicite a su Médico de Atención Primaria la derivación a un Dermatólogo Especialista que ofrezca Servicio de Prueba de Parche, ya sea en un Hospital Estatal o en un Consultorio Privado.
DERMATITIS ALÉRGICA DE CONTACTO
Información del paciente
Contact allergy is the state of being sensitised to a hapten.
What is a hapten, you may ask!
Good question!!
Essentially, a hapten is a substance, usually a chemical, that becomes presented to the immune system of a person, usually through physical contact between that substance and that person. Then the hapten becomes conjugated (attached) to an immune cell in a persons body, and this complex of hapten + immune cell then becomes an allergen. This allergen may then cause the development of symptoms of Allergic Contact Dermatitis. In many contexts, the substance is commonly known as an allergen, though it is technically and more correctly called a hapten.
Haptens are typically small, chemically reactive molecules with low molecular weight. They need to penetrate the horny layer of the skin (stratum corneum) in order to conjugate to (bind to) epidermal and dermal proteins forming “hapten-carrier complexes” with antigenic properties that are capable of causing contact allergy. Examples of widely recognised haptens include nickel, formaldehyde and preservatives in cosmetics.
You may also ask what is an antigen...
An antigen is (simply put) any substance with which the human body may develop an adverse reaction of one form or another.
Sensitisation to a hapten occurs when the accumulated exposure to that specific hapten surpasses a certain threshold. This threshold is individual and varies greatly between different persons. Some persons will develop an allergy the first time upon encountering a hapten, other persons can withstand a life-time of exposure to that hapten without becoming sensitised.
Allergic Contact Dermatitis (ACD) is a disease of the skin that emerges in people that are exposed to specific haptens after having developed contact allergy. Once allergic, the subject will respond with skin inflammation (redness, flaking skin or blisters) whenever exposed. Individuals handling haptens as part of their profession or work occupation run a higher risk of developing ACD.
Once that person has reacted (for example by the development of symptoms of Allergic Contact Dermatitis; ACD), then they are said to be sensitised to that hapten.
Once sensitised, if the person encounters that same (or a closely related) hapten again, then they will most probably react again with symptoms of ACD. Those reactions can be weaker or stronger than the first time around.
ACD accounts for 20% of all reported work-related skin diseases. Occupational fields with high occurrences of ACD include (but are not limited to) hairdressing, construction work, cleaning and health care.
Chronic once developed, and with no known cure, contact allergy is of major distress for those affected.
Do not confuse Allergic Contact Dermatitis which is a "Type IV" Delayed allergic reaction to a hapten with the classical "Type I" Immediate allergic reaction caused by usually biological substances ("allergens") such as pollens, mould spores, animal danders, house dust mite, foods, etc. Those usually cause respiratory reactions or gastro-intestinal reactions.
These allergens are identified usually by Skin Prick Tests
(not Skin Patch Tests) or by blood tests to identify allergen-specific Immunoglobulin E (IgE).
Still confused?
More confused?
Unfortunately many Family Practitioners/Primary Care Practitioners are too.
That is why the involvement of a Specialist Dermatologist or Specialist Allergist is advised whenever possible.
For further information, please see the list of recommended reading at the end of this section on Patient Information.
CONCEPTO DE PRUEBA DE PARCHE
Información del paciente
Diagnóstico de dermatitis alérgica de contacto
Los síntomas de una alergia de contacto, como picazón, enrojecimiento y lesiones cutáneas, pueden tratarse con cremas con esteroides y otros productos farmacéuticos similares, así como con diversos productos naturales. Sin embargo, el mejor tratamiento es evitar las sustancias problemáticas que causan la dermatitis alérgica de contacto (ACD). Por lo tanto, la identificación precisa y fiable de estas sustancias problemáticas es un requisito previo esencial.
Las pruebas de parche se utilizan para identificar las sustancias generalmente químicas que están causando la ACD del paciente, imitando el proceso de contacto de manera científica y controlada.
Se sabe que más de 550 sustancias sensibilizantes diferentes causan ACD, aunque hay muchas más sustancias que tienen el potencial de causar sensibilización y ACD posterior.
El dermatólogo o alergólogo seleccionará cuál de estas sustancias utilizar en una prueba de parche, basándose en las circunstancias individuales del paciente, la presentación clínica, cualquier sospecha basada en su experiencia clínica y en qué sustancias de prueba de parche están disponibles para él.
Por lo general, habrá un panel de prueba estándar de haptenos que se utiliza para todos los pacientes con ACD. Pueden ser tan solo 20 sustancias diferentes o hasta 90 sustancias. Esa Serie Base o Estándar puede complementarse con una Serie Especializada de haptenos que puedan ser más relevantes para el paciente y su ACD. Además, también pueden existir muestras de haptenos procedentes del propio lugar de trabajo o del entorno doméstico del paciente (como productos químicos, cosméticos, etc.).
Tenga en cuenta que no existe un análisis de sangre in vitro equivalente o comparable para identificar los haptenos que causan la ACD en un paciente en particular.
Prueba de punción cutánea
La prueba del parche cutáneo no es lo mismo que la prueba cutánea por punción, que los alergólogos utilizan para identificar sustancias generalmente biológicas, como polen, moho, caspa de animales y alimentos, que pueden causar alergias respiratorias y alimentarias. Esto se conoce como reacción de hipersensibilidad inmediata de tipo I e implica la producción y acciones de anticuerpos IgE dirigidos contra los alérgenos problemáticos.
Saber qué hapteno está causando la ACD ayuda al paciente a evitar estos haptenos, por lo que no invoca la ACD y, en consecuencia, mejora de manera efectiva la calidad de vida del individuo.
PROCEDIMIENTO DE PRUEBA DE PARCHE
Información del paciente
In order to perform a diagnostic Patch Test, two crucial components are required:
The Patch Test procedure is an epicutaneous diagnostic provocation test using standardised patch test Haptens and patch test Chambers on Chamber Strips.
The haptens may be a single chemical, (such as formaldehyde) or may be a mix of related chemicals (such as thiuram mix).
This mix counts as a single patch test.
Patch testing is performed by applying haptens into small chambers mounted on tape. These are known as Patch Test Chambers on Patch Test Chamber Strips. Once the different Haptens have been applied to the Chambers, then the Chamber Strips are applied to the patient’s skin, most usually on their back, for a period of 48 hours, or 72 hours.
In a person who is sensitised to one or more of the haptens in the Chamber Strips, the patient's immune system will react by producing a characteristic reddening, itchiness or superficial lesion at the site of the problem Hapten. This is a positive patch test reaction. There are grades of positivity.
The Hapten preparations used in patch testing should ideally be specifically developed for patch testing purposes.
The Patch Test Haptens manufactured by Chemotechnique of Sweden are prepared by mixing high-purity fine-particle ground raw material with high-grade white petrolatum. A few haptens are in liquid form, either ethanol or water.
The Patch Test haptens are grouped into Series. The typical patch test screening is performed by testing a Baseline Series (sometimes referred to as a Standard Series) alongside additional Specialist Series. The Baseline Series contains a selection of common haptens with high prevalence in a specific geographical region. For example, there is a British Standard Series that the leading patch test Specialist Dermatologists in Gt. Britain have agreed are the most important contact haptens for patients in GB. Similarly, there is a Swedish Baseline Series, a European Baseline Series, an Australian Baseline Series, a New Zealand Baseline series, no less than several different American Series, and so on. These different Series can range in number from just 20 different haptens to 90 haptens.
Specialist Series contains haptens that have high prevalence (frequency of occurance) in certain occupations, such as Paints, Adhesives, Dental, etc. There are also Specialist Series based on particular groups of chemicals found in the household, such as Cosmetics, Sun-Screens, Perfumes, Shoes, etc.
The Patient may be asked by the Dermatologist to provide samples of substances that the Specialist suspects may be the problem haptens from the patients own workplace or own home.
The combination of series (Baseline/Standard Series and/or Specialist Series and/or Patients own substances) will be determined by the Specialist, based on the specific patient history.
To ensure that the hapten remains in direct contact with the skin for the time required (48 or 72 hours) to create a standardised controlled reaction, a Patch Test Chamber Strip is needed.
A Patch Test Chamber Strip is composed of sets of chambers mounted on an adhesive tape. The purpose of the patch test chambers is to provide a defined area in which the skin will be exposed to the haptens during the testing. Due to the nature of patch testing it is important that the Patch Test Chamber Strips used have good occlusion to the skin and that they are made of inert materials that do not interfere with the haptens tested.
The patch test chamber strips classically comprise 10 test sites, so for 10 patch test haptens.
The chambers and therefore also the hapten that is applied to the skin under the chamber, should ideally be square in shape so as to differentiate from any irrelevant skin condition that will be either round or irregularly shaped.
Consider that a Standard or Baseline Series may be 30 to 90 tests, plus a Specialist Series that may be of 10 to 40 tests, plus possibly also a few samples of the patient's own substances, then that will easily total 100 or more patch tests. This means 10 or more Chamber Strips to be affixed to the patient's back for a period of 48 or 72 hours.
The haptens are added to the chamber strip test sites in a logical and controlled order, so that any skin reactions can easily be assigned to specific haptens.
When the patches are affixed to the patient's back, their location is marked with a special pen so that after the patch test chamber strips have been removed, any reactions seen can still be allocated to specific haptens in a specific chamber strip.
Patch testing involves a number of scheduled patient appointments within a one-week timeframe. After the application of the patch tests on Day 0, two or sometimes three appointments are needed for readings of any reactions. The main reading should be performed at 48 hours or 72 hours, immediately after the removal of the Patch Test Chamber Strips. Another reading should be performed by the Dermatologist or Allergist a full week (Day 7) after the initial test application for haptens that may show delayed reactions. Only then after these readings of any reactions can the Specialist provide the diagnosis and confirm the identity of the problem substances, and discuss with the patient the future course of action to avoid the identified problem substances. This of course requires an in-depth knowledge of what substances are found in workplaces and in household products.
Occasionally, with some haptens, a very late reaction will develop, so after 7 days. Some substances are more likely to cause this than others. This reaction might be noticed by the patient, due to the itching. If this occurs, then it is recommended that the patient take a digital photograph of the reaction (not so easy!) and email that to their Dermatologist for them to include in the test results. This could possibly be a very significant finding. Ideally, the reaction site will still be identifiable by the location marks which will hopefully still be present on the patients back.
Patch Test Reactions
Normal Reactions:
In sensitised patients, exposure to haptens during the patch testing procedure will normally result in a miniature eczema (normal patch test reaction). In addition to the visual imprints on the skin from each chamber, a slight erythema from the frames should be visible as a sign of good occlusion. The erythema generally subsides within 30 minutes after removal of the Chamber Strips. The erythema may however prevail for up to 24 hours or more for patients with sensitive skin. Itching at the site of application of the Patch Test Units is not uncommon; it can either be caused by a positive patch test reaction or may occasionally be due to tape irritation.
Adverse Reactions:
A strong positive reaction may result in a flare-up of an existing, or sometimes a previous, dermatitis. Such flare-up reactions usually indicate that the responsible hapten is or has been, respectively, the cause of the dermatitis.
Sensitisation by patch testing is a rare but potential complication of patch testing. It is regarded as a positive patch test reaction generally 2 weeks after an initially negative response at the same patch test site. Rarely localised transient hyper-pigmentation or hypo-pigmentation may occur. A positive patch test reaction can rarely persist for up to several weeks.
Patients are instructed to report any side effects to the Specialist.
RECOMENDADO
OTRAS LECTURAS
Información del paciente
Existen innumerables fuentes de información disponibles para una persona que busca conocimientos y explicaciones sobre la dermatitis alérgica de contacto y otras afecciones cutáneas similares, así como sobre las pruebas de parche.
Por supuesto, la mejor fuente es un dermatólogo consultor, pero puede resultar inaccesible, costoso o inconveniente.
En línea existen numerosas fuentes de información buenas y acreditadas; Por lo general, los sitios web de varias sociedades médicas profesionales para dermatólogos, ya que brindan un servicio no solo a sus dermatólogos miembros sino también a los pacientes.
A continuación se recomiendan sitios web o páginas web adecuados para leer más.
1. https://dermnetnz.org/topics
Sitio web de Nueva Zelanda para pacientes de dermatología
2. https://www.dermcoll.edu.au/a-to-z-of-skin/
Sitio web australiano para pacientes de dermatología
3. www.bad.org.uk / https://www.skinhealthinfo.org.uk/
Sitio web del Reino Unido para pacientes de dermatología
4. https://www.aad.org/public/diseases
Asociación de la Academia Estadounidense de Dermatología
5. https://www.mayoclinic.org/diseases-conditions/contact-dermatitis/symptoms-causes/syc-20352742
Páginas web de Mayo Clinic sobre dermatitis alérgica de contacto
6. https://www.healthline.com/health/contact-dermatitis
Páginas web de Healthline sobre dermatitis alérgica de contacto
7. https://www.nhs.uk/conditions/contact-dermatitis/
Páginas web del Servicio Nacional de Salud del Reino Unido sobre dermatitis alérgica de contacto
8. https://nationaleczema.org/eczema/types-of-eczema/contact-dermatitis/
Páginas web de la Asociación Nacional de Eccema de EE. UU. sobre dermatitis alérgica de contacto
9. https://emedicine.medscape.com/article/1049216-overview
Páginas web de eMedicine de EE. UU. sobre dermatitis alérgica de contacto
10. https://en.wikipedia.org/wiki/Patch_test#:~:text=A%20patch%20test%20is%20a,testing%20or%20skin%20prick%20testing.
Artículo de Wikipedia sobre pruebas de parches
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