ATOPIC DERMATITIS

Atopic dermatitis (AD), a specific form of eczema, is the most common chronic inflammatory skin disease. It affects both children and adults and can flare up or come and go throughout your life. Atopic dermatitis is the most common type of eczema. Eczema is a term describing a group of skin conditions that result from inflammation.

How common is atopic dermatitis?

AD is seen in approximately 10% to 30% of children and 2% to 10% of adults in developed countries. This prevalence has increased two to three-fold in recent decades. AD has a higher incidence at higher latitudes, which may be related to decreased sun exposure and lower humidity levels. AD is divided into three subsets based on the age of onset:

• Early-onset AD (birth to 2 years old):  most common type of atopic dermatitis, with approximately 60% of cases starting by age 1. Sixty percent of cases resolve by 12 years old.
• Late-onset AD:  symptoms begin after the onset of puberty.
• Senile onset AD: an unusual subset with onset in patients older than 60 years old.

What are the causes of AD?

AD has a complex etiology including genetic and environmental factors which lead to abnormalities in the epidermis and the immune system. AD is part of the atopic triad (atopic dermatitis, allergic rhinoconjunctivitis, and asthma) which may start simultaneously or in succession in what is known as the "atopic march." Patients with the atopic triad have a defective barrier of the skin, upper respiratory, and lower respiratory tract which leads to their symptomatology. If one parent is atopic, there is more than a 50% chance that their offspring will develop atopic symptoms. If both parents are affected, up to 80% of offspring will be affected. Genetic alterations include loss of function mutations of filaggrin (Filament Aggregating Protein), an epidermal protein that is broken down into natural moisturization factor. Filaggrin mutations are present in up to 30% of atopic dermatitis patients and may also predispose patients to ichthyosis vulgaris, allergic rhinitis, and keratosis pilaris. Food hypersensitivity may also cause or exacerbate AD in 10% to 30% of patients. Ninety percent of such reactions or flares are caused by eggs, milk, peanuts, soy, and wheat. (https://www.ncbi.nlm.nih.gov/books/NBK448071/) 

What are the symptoms and types of AD?

Depending on the type of dermatitis, symptoms may include:

• A skin rash
• Dry or cracked skin
• Itchy skin
• Red, purple, brown or gray skin discoloration
• Small, fluid-filled bumps or crusting 
• Swelling

The symptoms can affect specific areas of the body and present as face dermatitis, flexural dermatitis (affecting skin folds for e.g. at elbows or knees), eyelid dermatitis, head & neck dermatitis, hand dermatitis, nipple dermatitis, etc. 

Appearance of AD can change overtime from round, discolored and scaly patches referred as “discoid dermatitis” to firm, dry, raised bumps referred as “prurigo nodularis”. (https://my.clevelandclinic.org/health/diseases/24299-atopic-dermatitis) 

How is AD diagnosed?

Your health care provider will talk with you about your symptoms, examine your skin and review your medical history. Tests to identify allergies and rule out other skin conditions may be required. Patch testing of the skin helps to diagnose specific types of allergies causing your dermatitis. 

In some cases, your provider may recommend a skin biopsy. This is a test to look at a sample of your skin more closely in a lab under a microscope.

How is AD treated?

If regular moisturizers don`t work, your healthcare provider may prescribe medicated creams. 

• Creams or ointments with a calcineurin inhibitor might be a good option for those over age 2. Examples include tacrolimus (Protopic) and pimecrolimus (Elidel). Apply it as directed, before you moisturize. Avoid strong sunlight when using these products.
• If there is infection, your healthcare provider might prescribe antibiotics. 
• For more severe symptoms, pills like cyclosporine, methotrexate, prednisone, mycophenolate and azathioprine may be prescribed. These pills are effective but can't be used long term because of potential serious side effects.
• Injectable biologics (monoclonal antibodies) dupilumab (Dupixent) and tralokinumab (Adbry) might be options for people with moderate to severe disease who don't respond well to other treatment. 
• Alternative therapies in the form of corticosteroid wet dressings, ultraviolet phototherapy, relaxation, counselling and biofeedback can further add to the benefits of main treatment regime. (https://www.mayoclinic.org/diseases-conditions/atopic-dermatitis-eczema/diagnosis-treatment/drc-20353279)