Atopic dermatitis, better known by the term eczema, is a chronic skin disease that is often associated with other allergic diseases, namely bronchial asthma and rhinitis, usually appearing before the respiratory manifestations. It preferentially affects pediatric age groups and in 80% of cases manifests itself during the first year of life.
How frequent is dermatitis?
In Portugal, it is estimated that about 10% of children are affected by the disease, being in this age group the most frequent chronic dermatologic disease, although only 1 to 2% suffer from severe complaints. In most situations the disease tends to improve greatly and even disappear with age, although it may remain for life; the persistence of this entity is more observed in cases where the onset is later.
How does atopic dermatitis manifest itself?
Diagnosis is based on the presence of pruritus ("itching"), associated with cutaneous signs such as redness, exudation, dryness and flaking of the skin and, in more prolonged situations, there may be scarring caused by persistent itching. The location of these lesions varies according to age group: younger children show preferential involvement of the head, sometimes just behind the ears, and the extensor surfaces of the limbs, while older children and adults tend to manifest the disease on the flexor surfaces (behind the knees and in front of the elbows); adolescents are also frequently affected on the eyelids and peri-labial region.
The confusion with other entities that may cause intense pruritus should be duly evaluated, not only to exclude them but also due to the probability of simultaneous occurrence, particularly of infections. The clinical evaluation carried out allows the exclusion of these situations, as well as the characterization of complications.
How is it diagnosed?
Complementary diagnostic tests include skin tests, if the skin is intact, and blood tests for antibodies, namely for environmental allergens and food allergens, allowing the characterization of some of the aggravating factors.
What is the treatment for atopic dermatitis?
General measures should be considered in the treatment of atopic dermatitis:
- wear only cotton clothing to avoid sweating (sweating increases the itching)
- wash new clothes before first use (to prevent irritative reactions)
- avoid large exposures to dusty environments (drying effect and irritation).
If you have identified foods that can cause the appearance or worsening of skin lesions, these should be avoided; however, beware of poorly-targeted generalized diets because of the nutritional risks and associated costs. You should also avoid contact with allergens in the environment to which you are sensitized (examples: house dust mites, pets).
It is very important to moisturize the skin, using an emollient (moisturizer), which should be applied immediately after bathing (warm water) in order to avoid evaporation of the water retained on the skin during bathing. Emollients with a predominance of fatty acids (omegas) and not water should be preferred, which, as with multiple washes, can even lead to skin dryness and worsening of the disease.
Most of the situations will respond to this type of measures; if, despite them, the itching persists (even without lesions), it should be controlled, to avoid itching, which is itself a conditioner of the worsening of the disease and, consequently, of more itching. This cycle can then be minimized by moisturizing the skin, always keeping the nails well cut, and using oral antihistamines, which can also be used daily for long periods in order to stabilize the disease. In the most severe forms or if acute symptoms appear, corticosteroids in the form of cream or ointment should be used (using those with the lowest possible potency; on the face preferably hydrocortisone 1%); if the intensity and extension justify it, oral corticosteroids can be administered for very short periods.
Note: Because corticosteroids in tablet and capsule form can cause serious side effects, doctors only use them as a last resort for hard-to-treat individuals. These oral drugs can stunt growth, weaken bones, inhibit adrenal gland function, and cause many other problems, especially in children. Moreover, their beneficial effects are only temporary.
In some cases, anti-infective therapy may be necessary. In particular conditions, the specialist may propose the use of other treatments.
Seborrheic dermatitis is an inflammation of the superficial layers of the skin that causes scales on the scalp, face, and occasionally other areas. It usually affects several members of the same family, and cold weather often makes it worse.
What are the symptoms?
Seborrheic dermatitis usually appears gradually, causing a dry or greasy scaling of the scalp (dandruff), sometimes itching, but without hair loss. In the most severe cases yellowish or reddish papules appear along the hairline, behind the ears, in the ear canal, over the eyebrows, in the bridge of the nose, around the nose, and on the chest. In infants under one month, seborrheic dermatitis can cause a crusty, yellow, thickened lesion (infant's cap) and sometimes yellow scaling behind the ears, and red papules on the face. Often with the scalp rash there will also appear another, very persistent rash in the diaper area. Older children can develop thick, persistent, large-scaled lesions on the skin.
Treatment
In adults, the scalp can be treated with shampoos that contain zinc, selenium sulfide, salicylic acid, sulfide or tar. As a rule, the person uses these shampoos daily until the dandruff is controlled, and then twice a week. Generally, the treatment should continue for several months. If the dermatitis reappears after stopping the treatment, a new start can be made.
Lotions containing corticosteroids are also used on the head and other affected areas. Only lotions with not very potent corticosteroids, such as 1 % hydrocortisone, should be used on the face. Even weak corticosteroids should be used with caution, under medical or pharmaceutical advice, because prolonged use can reduce the thickness of the skin and cause other problems. If corticosteroid therapy does not eliminate lesions, in some cases a cream with ketoconazole is used.
In infants and young children who have a thick scalp crust - see the article on cradle cap.
Contact dermatitis is an inflammation caused by contact with a particular substance. The eruption is confined to a specific area and is usually well-defined.
Substances that cause contact dermatitis can cause the skin to become inflamed by one of two mechanisms: irritation (irritant dermatitis) or an allergic reaction (allergic dermatitis). Even mild soaps, detergents and certain metals can irritate the skin after frequent contact. Sometimes repeated exposure, even to water, can dry and irritate the skin. Strong irritants such as acids, alkalis (like stain removers), and some organic solvents (like acetone, used to remove nail polish) can cause changes to the skin in a matter of minutes.
In an allergic reaction, the first exposure to a particular substance (or sometimes the first few exposures) does not cause any symptoms, but the next exposure can cause burning and dermatitis within 4 to 24 hours. People can use (or be exposed to) certain substances for years without problems and then suddenly develop an allergic reaction. Even the ointments, creams and lotions used to treat dermatitis can cause such a reaction. About 10 percent of women are allergic to nickel, the most common cause of jewelry dermatitis. It is also possible to develop dermatitis from any material that a person touches while working (occupational dermatitis).
A dermatitis that occurs when one touches certain substances and then exposes the skin to sunlight is called photoallergic or phototoxic contact dermatitis. These substances include sunscreens, after-shave lotions, certain perfumes, antibiotics, tar (coltar) and oils.
What are the symptoms?
The effects of contact dermatitis range from mild, passing redness to severe inflammation and blistering. The eruption often consists of tiny, itchy blisters (vesicles). At first the lesions are limited to the contact area, but later they can spread. The affected area can be very small (e.g. earlobes, if earrings cause dermatitis) or it can cover a large area of the body (e.g. if dermatitis is caused by a body lotion).
When you suppress the substance that causes the rash, the redness usually disappears within a few days. The blisters may ooze and form crusts, but they dry up quickly. Residual scaling, itching, and temporary thickening of the skin may last for days or weeks.
Diagnosis
It is not always easy to determine the cause of contact dermatitis because the possibilities are endless. Also, most people are not aware of all the substances that touch their skin. The location of the initial rash is often an important factor.
If the doctor suspects contact dermatitis but does not discover the cause through careful elimination, he or she can perform the patch test. For this test, small adhesive patches with substances that usually cause dermatitis are placed on the skin for two days to see if there is a rash under any of them.
Although very useful, this patch test is complicated. The doctor must decide which substance to test, how much of each substance to apply, and when to test. Also, the results of the test can be difficult to interpret. Tests can be falsely positive or negative. Most people can find the source of their dermatitis without this patch test, systematically eliminating possible causes. In any case, it is a test that can contribute important data to identify the cause.
Treatment
Treatment consists of eliminating or avoiding whatever is causing the contact dermatitis. To prevent infection and avoid irritation, the affected person should clean the area regularly with mild soap and water. The blisters should not be burst. Dry bandages can also help prevent an infection.
Corticosteroid creams or ointments usually relieve the symptoms of mild contact dermatitis, unless the person has many blisters, as in the case of poison ivy. Corticosteroid tablets (such as prednisone) are sometimes given in cases of contact dermatitis. Although in some situations antihistamines relieve itching, they are not particularly beneficial in most cases of contact dermatitis.
In case the causative allergen is identified and is an object that the person comes into contact with on a small area of skin, to prevent contact dermatitis upon further contact, so-called barrier creams or films that insulate the skin can be used. Sweetcare has several alternatives.
Common causes of allergic contact dermatitis
- Cosmetics: depilatory chemicals, nail polish, acetone, deodorants, moisturizers, aftershave lotions, perfumes, sunscreens
- Metal compounds (in jewelry): nickel
- Plants: several varieties of sumac, ambrosia, primrose
- Drugs contained in skin creams: antibiotics (penicillin, sulfamides, neomycin), antihistamines (diphenhydramine, promethazine), anesthetics (benzocaine), antiseptics (thimerosal), stabilizers
- Chemical compounds used in the manufacture of garments: shoe dyes, waterproofing agents and antioxidants in gloves, shoes, underwear and other garments.