What Is Atopic Dermatitis?
Atopic dermatitis is a very common disease and occurs mainly in childhood. It has a strong association with genetics and the symptoms include dry skin, itchiness, redness, and eczema.
Some authors consider this disease to be an additional expression of an atopic syndrome, in which patients develop various conditions throughout their lives. This includes asthma and other forms of dermatitis.
The different faces of atopy
The term atopy is used to describe those patients who tend to generate repeated allergic reactions. These, in addition, usually involve many organs and systems.
There’s a theory that suggests the existence of the allergic march. This is defined as the natural history of an allergic patient, who may develop various diseases throughout their life. Depending on age, the appearance of some conditions is more common, such as food allergies in children under 2 years of age and rhinitis in schoolchildren.
Atopic dermatitis is inflammation of the skin for allergic reasons. It involves moderate inflammatory reactions and usually appears in the first six months of life. In many cases, it’s preceded by food allergies. This disease usually has a similar proportion in both sexes.
Clinical manifestations of atopic dermatitis
The skin symptoms of atopic dermatitis are quite varied and occur together. Most patients have a family history of allergies, especially asthma.
Dry skin or xerosis
This occurs in most patients and is accompanied by mild to moderate scaling. It’s thought to be due to changes in lipid metabolism and increased water permeability in the epidermis.
This leads to problems with the natural hydration of the skin. In fact, these macronutrients have an important role in preventing water loss under the effect of sunlight. That’s why there’s redness, and this is the symptom that most often attracts the attention of parents.
This term refers to a set of skin disorders with very diverse causes, in addition to atopy. The main feature is the itching of the skin that appears abruptly.
It’s possible to find very diverse lesions associated with eczema:
- Desquamation: This is produced by the loss of the most superficial layer of the skin.
- Swelling (edema): This is characterized by localized fluid retention, typical of inflammatory phenomena. Sometimes it’s a consequence of scratching.
- Vesicles: These are primary dermatological lesions and are small, slightly raised, and with little liquid content.
- Bullae: These can be formed by the confluence of the vesicles.
- Erythema: Reddening of the skin.
This condition is characterized by hypopigmented areas of variable size. This means that the lesions acquire a softer or more subdued tone compared to the patient’s skin. Therefore, they have a whitish appearance and are very pale.
They’re usually asymptomatic and their appearance tends to worsen when there’s exposure to sunlight. Furthermore, it’s more common in young patients than in adults and is found on extremities exposed to the sun.
These lesions are often confused with a fungal infection known as tinea versicolor, which has the same characteristics, but itching is added. It’s part of the differential diagnoses.
Itching or pruritus
This is an uncomfortable sensation because it appears progressively and isn’t completely relieved by scratching. In fact, in many patients, it can lead to open lesions that, if not cleaned, lead to bacterial superinfection.
Some conditions can trigger the symptoms, such as stress, the consumption of some allergenic foods, and infections in any organ.
This term refers to inflammation of the lips. When it affects the corners of the mouth, it’s known as angular cheilitis. It’s very annoying and can spread around the entire mouth.
In the colder times of the year, despite the fact that the other symptoms of atopic dermatitis aren’t present, the lips may become dry. In these cases, the habitual and spontaneous practice of lubricating them with saliva tends to make the problem worse.
The causes of atopic dermatitis
This condition is the result of the interaction between genetic and environmental factors. Because of the strong association with heredity, it’s likely that genetics plays a larger role.
There are mutations related to atopic dermatitis that affect the genes associated with the production of filaggrin, a very abundant constituent of keratin in the epidermis. In addition, other mutations are related to the proper functioning of the cells of the immune system.
Exposure to external substances that act as allergens is necessary to unleash the crises. That is, they’re capable of inducing an exaggerated immune response that causes, as a consequence, allergy.
The diagnosis of atopic dermatitis
Due to the lack of direct diagnostic tests and its very characteristic manifestations, atopic dermatitis is usually detected clinically. For this, it’s important to provide the doctor with information regarding the family history of atopy and the different signs.
The specialist in charge of diagnosing and treating these diseases is the dermatologist, although other doctors (allergists, family doctors, pediatricians, or internists) can also do it.
As there are no specific complementary tests available, it’s common for doctors to consider some differential diagnoses. Some of the most common are the following:
- Seborrheic dermatitis: In advanced stages, it can generate reddened lesions (erythema) and scaling, similar to cases of atopic dermatitis. However, this condition is characterized by abundant sebum production.
- Scabies: This is a parasitic infection caused by the Sarcoptes scabiei mite that produces very small, itchy raised lesions.
- Pityriasis versicolor: This is a superficial mycosis (fungal infection) that closely resembles the lesions of the pityriasis alba type that were mentioned above.
Is there treatment for atopic dermatitis?
Yes, treatments are available for atopic dermatitis. Those patients who tend to have disease recurrences may need ongoing monitoring with an allergist.
When the disease occurs in babies, it’s important to take into account a series of measures that can alleviate the symptoms or prevent their appearance. These include frequent grooming, applying emollient (moisturizing) creams after bathing, and prioritizing short showers. It also helps to avoid exposure to heat and foods high in histamine, such as strawberries, eggs, and shellfish.
They’re usually used in all cases, especially when the lesions are very localized and it’s easy to apply the creams. The drugs most used by dermatologists are steroids, which are compounds derived from cholesterol. These have potent anti-inflammatory activity.
Some of the most commonly used are hydrocortisone and triamcinolone. In some regions, such as the face and large body folds, other drugs and indications are necessary due to the possibility of adverse effects.
In recent years, the use of topical immunomodulators, such as pimecrolimus, has increased. These are capable of regulating the activity of lymphocytes, decreasing the inflammatory response of the disease.
This last section refers to those drugs that are ingested orally:
- Antihistamines: Also known as anti-allergy medications, these help decrease symptoms such as itching and are often given with topical steroids. Loratadine and cetirizine are very common options.
- Steroids: Doctors may indicate these drugs orally in exceptional cases when there’s a poor response to topical treatment.
- Immunomodulators: Like the topical medications that we mentioned in the previous section, these drugs can reduce the inflammatory response. They’re not common and are also reserved for special cases.
Controlling atopic dermatitis is a lifelong matter
Atopic dermatitis requires an intensive approach, as the symptoms are recurrent and bothersome. The experience of a dermatologist can be essential to choose the most appropriate treatments in each case. The patient’s age and concomitant diseases should also be considered.
In any case, the initial measures are hygienic-dietary. Small changes in routines make a big difference that people with the condition can take advantage of.It might interest you...
- Aviña J, Castañeda D. Marcha alérgica: el camino de la atopia. Alergia, Asma e Inmunología Pediátricas 2006;15(2):50-56.
- Garavís J, Ledesma M, De Unamuno P. Eccemas. Medicina de Familia – SEMERGEN 2005;31(2):67-85.
- Medina D. Dermatitis seborreica: una revisión. Dermatología CMQ 2014;12(2):135-141.
- Pérez-Cotapos M, Soledad M, Sáenz M. Dermatitis atópica. Revista Médica de Clínica Las Condes 2011;22(2):197-203.
- Fierro, Jorge Arturo Aviña, and Daniel Castañeda Gaytán. “Marcha alérgica: el camino de la atopia.” Alergia, Asma e Inmunologia Pediatricas 15.2 (2006): 50-56.
- Cebrián Fernández, Ana. “Papel de la histamina en la alimentación: revisión bibliográfica de las distintas patologías que puede ocasionar su exceso en el organismo.”
- Barragan, Diana Stefania Evangelista, et al. “Dermatitis atópica (ECCEMA) infantil.” RECIAMUC 3.3 (2019): 192-207.
- Ricardo Alonso, Orayne Ekatherina, et al. “Aspectos de interés sobre la etiopatogenia de la dermatitis atópica.” Revista Médica Electrónica 40.4 (2018): 1139-1148.
- Weidinger, S., H. Baurecht, and J. Schmitt. “A 5‐year randomized trial on the safety and efficacy of pimecrolimus in atopic dermatitis: a critical appraisal.” British Journal of Dermatology 177.4 (2017): 999-1003.