Atopic dermatitis is a very common, most common chronic (long-lasting) skin disease that affects a large proportion of the world’s population. Some call it eczema, dermatitis or atopy. It is most commonly a type of skin allergy or sensitivity, and is often associated with an atopic triad that includes asthma, allergy (hay fever), and eczema. There is a known hereditary component of the disease that is seen in many families. The main signs of the disease include skin rash and itching.
The word “dermatitis” means inflammation of the skin. “Atopic” refers to diseases that are hereditary, tend to spread in families, and usually occur together. In atopic dermatitis, the skin becomes increasingly itchy and inflamed, causing redness and swelling of the skin, its cracking, exudation, scabs and scales. Dry skin is very common and causes some of the typical rashes.
Although atopic dermatitis can occur in all age groups, it most commonly affects young people and young children. In some cases, it can occur in adulthood or be first revealed in adulthood. A large number of patients generally have a chronic course with various ups and downs. In most cases, there are periods when the disease worsens, called exacerbation or an outbreak of the disease that alternates with periods when the condition of the skin improves or it clears up completely causing a condition called remission. A lot of children with atopic dermatitis stay inside permanent remissions of the disease as they age although their skin may remain still dry and easily irritated.
Multiple factors can trigger exacerbation of atopic dermatitis including dry skin, seasonal allergies, exposure to harsh soaps and detergents, some creams, and cold weather. Environmental factors may activate the symptoms of atopic dermatitis in elderly patients who have a non-hereditary form of atopic disease.
What is the difference between atopic dermatitis and eczema?
Eczema is used as a general term for many types of dermatitis and allergic-type skin rashes. There are different types of eczema, such as allergies, contact, irritation and numerical eczema. Several other types have very similar symptoms. Different types of eczema are listed and briefly described below. Atopic dermatitis is a specific skin disease associated with three conditions that include eczema, allergy and asthma. Usually not every component is present at the same time, but usually these patients are prone to developing one of the three related symptoms.
Types of eczema
∙ Contact eczema: a local reaction that includes redness, itching, and burning of the skin that occurs after skin contact with anallergen (to an allergic substance) or with irritants such as acids, cleansers, or other chemicals.
∙ Allergic contact eczema: a red, itchy, secreting reaction that occurs when the skin comes in contact with substances that the immune system accepts as a foreign body, such as certain preservatives in creams and lotions, some metals (nickel, cadmium), dyes in fabrics , soaps, detergents, etc.
∙ Seborrheic eczema (also called seborrheic dermatitis or seborrhea): is a very common form of mild skin inflammation of unknown cause that manifests as yellow, oily, scaly patches on the scalp on the face, ears, or (sometimes) other parts of the body. It is commonly known as dandruff in adults or scalp in children.
∙ Numular eczema: Coin-shaped eczema (circle) is an isolated plaque of irritated skin – most commonly on the arm, back, thighs and lower limbs – that can be crusty, scaly and very itchy.
∙ Neurodermatitis: is a type of dermatitis that occurs as a result of scratching the skin. The main cause may be sensitization or irritation of localized parts of the skin that emphasizes the cascade of repeateditching– itching cycle. It can manifest as a scratched and stabbed field of skin. Sometimes scales on the scalp, lower limbs, wrists, or forearms cause localized itching (like an insect bite) that can be irritated by intense scratching.
Static dermatitis: irritation of the skin of the lower limbs, generally associated with circulatory problems and stagnation of the leg veins. It is most often black pigmentation, light brown or purple-red discoloration caused by congestion and blood retention in the veins of the legs. It is mostly seen on the legs with varicose veins.
Dyshydrotic eczema: irritation of the skin of the palms of the hands (most commonly) and of the lower part of the foot (less commonly) characterized by clean, very deep located blisters that itch and burn. It is sometimes described as ‘Tapioica pudding’ like a rash on the fingers.
How often does atopic dermatitis occur?
Atopic dermatitis is a very common disease spreading worldwide with an increasing incidence. It affects men and women equally and accounts for 10% to 20% of all referrals to dermatologists. Atopic dermatitis most commonly occurs in young people and children, and this incidence decreases with age. Scientists estimate that 65% of patients develop symptoms in the first years of life and 90% develop symptoms before the age of five. Onset after the age of 30 is much rarer and usually occurs after exposure of the skin to harsh living and working conditions. People living in urban areas and climates with low humidity seem to have an increased risk of developing atopic dermatitis.
About 10% of all adolescents and young children have an unpleasant experience with symptoms of atopic dermatitis. Approximately 60% of these children continue to have one or more symptoms of atopic dermatitis equally at adulthood.
What causes atopic dermatitis?
The cause of atopic dermatitis is not known, but the disease appears to result from a combination of genetic (hereditary) and environmental factors. The basis here seems to be hypersensitivity and increased itching. Evidence suggests that the disease is linked to other so-called atopic diseases such as seasonal allergies and asthma, which many people with atopic dermatitis have. Later in life, many children who outgrow the symptoms of atopic dermatitis go on to develop seasonal allergies or asthma. Although one disease is not directly caused by another, they may be related, so they give researchers a clue to understand atopic dermatitis.
While emotional factors and stress may in some cases exacerbate or initiate illness, they do not appear to be the primary or underlying cause of the disease. In the past, there was an opinion that atopic dermatitis was completely caused by emotional factors.
Is atopic dermatitis contagious?
It’s not. Atopic dermatitis is definitely not contagious and cannot be transmitted from one person to another by direct skin-to-skin contact. This fact is a relief for people who are in contact with people who have active atopic dermatitis, except when they have an active skin infection.
Some patients with atopic dermatitis get a secondary skin infection with staphylococcus (″ staph ″), herpes virus (cold inflammation) or the less common candida and other fungal infections. These infections can be contagious by skin contact between two people.
What are the symptoms of atopic dermatitis?
Although symptoms can vary from person to person the most common symptoms are dry, red skin that is very itchy. Itching is a major hallmark of the disease. Typical sites of involvement are the folds of the hands (elbow pits, wrists), knee pits, face, and palms. The area behind the ear and other parts of the body are less commonly affected. Itching is felt as an important factor in atopic dermatitis but scratching and rubbing in response to itching exacerbates the inflammation of the skin that is characteristic of the disease. Patients with atopic dermatitis develop a prolonged sensation due to increased sensitivity to itching, which manifests itself as an “itching – scratching” cycle. Extreme itching of the skin causes people to scratch which alternately worsens the itching and so on. Itching is the biggest problem during sleep, when the control of consciousness by scratching is reduced as is the presence of other external stimuli so that the itching is much more noticeable. Many patients report worsening itching in the early evening when they come home from work or school when there are minor external distractions.
In atopic dermatitis, the skin can change by scratching and lead to a skin infection. Some patients develop red, scaly skin, others develop thinner and rougher skin as a result of constant scratching and rubbing. This symptom is called lichenification. Some other patients develop papules or small raised growths on the skin. When the papules scratch, they can open (excrete) and become crusty and infected.
Can atopic dermatitis affect the face?
Yes. Atopic dermatitis can affect the skin around the eyes, eyelids, eyebrows and eyelashes. Scratching and rubbing the eye area can change the appearance of the skin. Some people with atopic dermatitis develop an atopic fold orDenny-Morgan fold on the outer fold of the skin under the eyes. Other people may have hyperpigmented eyelids, meaning that the skin of their eyelids turns black from inflammation or fever (allergic bruising on the eye). Stains on the eyebrows and eyelids can also be the result of scratching or rubbing.
The face is very commonly affected in a baby as a result of excessive scratching and becomes irritated from skin contact with her saliva.
Is skin type important?
Yes. Differences in the skin of people with atopic dermatitis can contribute to the symptoms of the disease. The epidermis is the outer layer of skin that is divided into two parts: the inner part which contains moist, living cells and the outer part which contains dry, flattened dead cells. Under normal conditions, the outer layer of the skin forms a barrier, keeping the remaining skin from drying out and protecting other layers of the skin from damage, irritation and infection. When this barrier is damaged or naturally thin, irritants attack the skin much more intensely.
The skin of people with atopic dermatitis loses a lot of moisture from the epidermal layer so the skin becomes very dry which reduces its protective ability. Therefore, the skin is very weak to correct the damage caused by staphylococcal and streptococcal bacterial infections, warts, herpes simplex and molluscum contagiosum (caused by a virus).
Cutaneous features of atopic dermatitis
∙ Lichenification: thin, rough, skin resulting from constant scratching and scratching
∙ Lichen simplex: refers to thin plaques of raised skin that result from repeated scratching and itching of the same part of the skin.
∙ Papules: small raised nodules. When we scratch they become crusty and infected
∙ Ichthyosis: dry, rectangular scaly skin, usually on the lower limbs and tibia
∙ Keratosis pilaris: small, rough nodules mainly on the face, upper limbs and thigh. This is also described as goose or chicken skin.
∙ Hyperlinear palms: increased number of skin folds on the palms
∙ Urticaria: Urticaria (red raised plaques) occurs mainly after exposure to allergens, at the beginning of sunbathing or after exercise or a warm bath.
∙ Cheilitis: inflammation of the skin around the lips
∙ Atopic fold(Dennie-Morgan fold): on the outer fold of the skin that develops under the eye
∙ Black circles under the eye: can be caused by allergies and atopy
∙ Hyperpigmented eyelids: eyelids that become darker in color after inflammation
∙ Prurigo knots
″ Grouped nipples″ are not actual nipples completely. These are small thinned protrusions of the skin caused by repeated shrinkage of the same skin.
What are the degrees of atopic dermatitis?
Atopic dermatitis manifests differently in each child. In children, atopic dermatitis typically begins around 6 to 12 weeks of age. It can first appear around the cheeks and chin as a colorful facial rash that can progress to red, scaly, moist skin. Such skin can become infected. When children start crawling exposed areas such as knees and elbows can also be affected. Children with atopic dermatitis may be restless and crying due to itching and discomfort. Most children improve at 18 months of age, although there is a normal risk of developing dry skin or eczema later in life.
In childhood, the rash appears behind the knees and inside the elbows on the side of the neck and on the wrist, ankles and hands. Usually the rash starts with pimpleswhich become harder and more scaly when scratched. The skin around the lips can be inflamed and constant licking of the area can lead to a small, painful scab.
Several cases of atopic dermatitis have been reported to affect growth so that children may be lower than average.
The disease can go intoremission(disease-free period). The length of remission varies and can last for months or even years. In some children, the disease improves over time and returns at the onset of puberty when hormones, stress, and the use of irritating care products or cosmetics can cause inflammation again.
Although most people develop atopic dermatitis in childhood, many symptoms of atopic dermatitis also occur in adults. It is also less common (but possible) for the disease to first appear in adulthood. The disease in adults is similar to that seen in children. In some adults, only the hands or feet may be affected, becoming dry, itchy, red, and cracked. Because of the above, the ability to work may be limited while long-term use of medications to treat the disease can cause complications. Adults with atopic dermatitis have a predisposition to irritating contact dermatitis, especially if they often wet their hands, wash their hands or are exposed to chemicals at work. Some people develop a rash around the nipples. These localized symptoms are difficult to treat and people usually do not tell the doctor because of shame or confusion. Adults can also develop cataracts that are difficult to detect because they do not produce early symptoms.
If you want to know more about diagnosis and treatment, see the related article Atopic Dermatitis Diagnosis and Treatment.
Ante Perica, MD dermatovenerologist
