Atopic Dermatitis

Atopic dermatitis is known as the "itch that rashes." The rashes presents after scratching because of severe itch/pruritis in the skin. This pruritis is believed to be caused by inflammatory molecules such as histamine that are released in the inflammatory reaction by mast cells. In the short term, the patient presents with red rashes and vesicles, if there was severe scratching, that subsequently begin to weep and ooze fluid as these vesicles begin to rupture. Crusting is also seen, which refers to the weeping of blood components onto the skin. The blood usually solidifies into a crust on the skin. Unfortunately, in the long-term, the skin becomes damaged and in order to protect itself for ongoing damage, it begins to harden, which is called lichenification. This leads to a leathery-like appearance of the skin.

Signs & Symptoms: chronic, pruritic eczematous skin lesions, with xerosis, lichenification (dermatitis at various stages; erythema +/- scaling +/- vesicles & crusts)
Child is often fussy and uncomfortable sec. to pruritis
Onset: 2-3 mos. old with periodic relapses and remissions into adulthood
Location: less than 10 months old - face and arm/leg extensors; greater than10 months old - neck and arm/leg flexor surfaces

Atopic Dermatitis Lesion Appearance and Diagnosis

These lesions evolve over time and are different at different stages of presentation within the lifecycle. In infancy, the lesions are found on the face, later in childhood, the lesions are found on the flexor surfaces of the skin, that include the joints that become smaller on flexion, such as the antecubital and popliteal fossa whcih are found on the arm and leg respectively. The diagnosis of atopic dermatitis is done clinically by a physician, through inspection of lesions and there pattern of distribution on the skin. There are no strong laboratory tests for dermatitis, except that pathological inspection of biopsies of the skin show an inflitrate into the skin with a high number of T cells and inflammatory cells.