Atopic Dermatitis

Atopic Dermatitis

Atopic dermatitis (AD) is a chronic, highly pruritic, eczematous skin disease that follows patients from early childhood into puberty and sometimes adulthood.

Also referred to as eczematous dermatitis, the disease often has a remitting/flaring course, which may be exacerbated by social, environmental, and biological triggers.

Prevalence

Approximately 15% in the US and Europe This represents a profound increase in recent years (from as low as 3% in 1960)

Natural History of Atopic Dermatitis

60% of pts develop AD by 1 year of age. 85% of pts develop AD by age 5. Earlier onset often indicates a more severe course. Many cases resolve by age 2, improvement by puberty is common. 50%-60% of pts develop respiratory allergies or asthma. 80% of occupational skin disease occur in atopics. It is rare to see AD after age 50.

Filaggrin

Filaggrins are filament-associated proteins which bind to keratin fibers in epithelial cells Individuals with truncation mutations in the gene coding for filaggrin are strongly predisposed to a severe form of dry skin, ichthyosis vulgaris, and/or eczema It has been shown that almost 50% of all severe cases of eczema may have at least one mutated filaggrin gene.

Infantile atopic dermatitis

Infants less than one year old often have widely distributed eczema. The skin is often dry, scaly and red with small scratch marks made by sharp baby nails. The cheeks of infants are often the first place to be affected by eczema +- head +- body. The diaper area is frequently spared due to the moisture retention of diapers. Just like other babies, they can develop irritant diaper dermatitis, if wet or soiled diapers are left on too long.

Toddlers and pre-schoolers

As children begin to move around, the eczema becomes more localized and thickened. Toddlers scratch vigorously and the eczema may look very raw and uncomfortable. Eczema in this age group often affects the extensor (outer) aspects of joints, particularly the wrists, elbows, ankles and knees. It may also affect the genitals. As the child becomes older the pattern frequently changes to involve the flexor surfaces of the same joints (the creases) with less extensor involvement. The affected skin often becomes lichenified i.e. dry and thickened from constant scratching and rubbing, In some children the extensor pattern of eczema persists into later childhood.

Atopic dermatitis in school-age children

Older children tend to have the flexural pattern of eczema and it most often affects the elbow and knee creases. Other susceptible areas include the eyelids, earlobes, neck and scalp. Many children develop a 'nummular' pattern of atopic dermatitis. This refers to small coin-like areas of eczema scattered over the body. These round patches of eczema are dry, red and itchy and may be mistaken for ringworm (a fungal infection). Mostly the eczema improves during school years and it may completely clear up by the teens, although the barrier function of the skin is never entirely normal.

Ichythosis vulgaris

Xerosis (dry skin)

Lichenification

Keratosis pilaris

Palmar hyperlinearity

Triggers
IrritantsWoolSoaps/detergentsDisinfectants“Occupational”Tobacco smokeMicrobial agentsStaph aureusViral infection?Dermatophytes Heat/Sweating Contactants incl. Dust mites Psychological Foods (IgE-induced) vaso-dilatory items Aeroallergens Hormones Climate


Managing AD(Preventative)
Prevent “scratching” or rubbinga) apply cold compresses to itchy skinCarefully eliminate all the triggers of itcha) environmental, occupational, and temperature controlb) bathing – soapless cleansers, Dovec) LUBRICATION – LUBRICATION LUBRICATION

Managing AD(Palliation)

Topical anti-inflammatory agentsa) corticosteroids (ointments>creams) more potent - when “acute” least potent needed for “chronic”b) Tacrolimus 0.1%, 0.03% ointment Pimecrolimus 1% Cream

Emollients

Atopic dermatitis patients frequently have dry skin which is aggravated during winter months. Xerosis (dryness) breaks the barrier function of the skin and promotes infection and inflammation. Ointments are preferred over lotions or creams. Emollients should be applied immediately after a soaking bath to retain the moisture. Emollients containing urea or alpha-hydroxy acids often cause stinging or burning sensations.

Corticosteroids

Corticosteroids

Calcineuron InhibitorsIndications

Protopic (tacrolimus) Ointment, both 0.03% and 0.1% for adults; 0.03% for children aged 2-15 years For short-term and intermittent long-term therapy in the treatment of moderate to severe atopic dermatitis in patients For whom the use of alternative, conventional therapies are deemed inadvisable because of potential risks or Who are not adequately responsive to, or are intolerant of alternative, conventional therapies. Elidel (Pimecrolimus Cream 1%) for patients 2 years of age and older For short-term and intermittent long-term therapy in the treatment of mild to moderate atopic dermatitis in non-immunocompromised patients For whom the use of alternative, conventional therapies are deemed inadvisable because of potential risks or Who are not adequately responsive to, or are intolerant of alternative, conventional therapies.

Antihistamines

Antihistamines give variable results in controlling pruritus of atopic dermatitis since histamine is not the only mediator of itching in atopic patients. Any of the non-sedating antihistamines like cetirizine, loratadine or fexofenadine may be used. The conventional antihistamines like diphenhydramine or hydroxyzine may give better results for their additional actions as a sedative or anxiolytic. Topical antihistamines should be avoided for their sensitizing potential (Doxepin cream).

Oral immunomodulators

Complications of AD
Secondary Infectiona) bacterialimpetiginization“super-antigenicity”b) viralLocalized – verruca, molluscum, herpesGeneraized – Dermatitis herpetiformis c) mycoticDermatophyteCandidal