Although, it is one of the most common causes of pruritus in children, this condition is poorly understood. Characterized by inflammatory hyperreactivity, the disease is currently believed to be caused by aberrancies in T-cell function, with immunoglobulin E overproduction and cell-mediated immune dysfunction in the skin.

Most children with atopic dermatitis have a family history of atopic disease (asthma, allergic rhinitis, or atopic dermatitis), and may later develop these conditions. The rash usually appears in susceptible patients during the first year of life, and starts on the cheeks and extensor surfaces of the extremities. As the child ages, the distribution changes to involve the flexor creases of the elbows and knees as well as the wrists, ankles, and trunk. The diaper area and nose are usually spared. The eruption consists of erythematous, poorly demarcated patches, and initially is exudative, later forming crusts. There may be associated papules or vesicles. With the scratching that ensues, the lesions become thickened or lichenified and may develop a surface scale. Pigmentation changes are common complications. Atopic dermatitis has a chronic, recurrent, or recalcitrant nature.

Contact dermatitis can be mediated by irritants or allergens.

Primary irritant dermatitis is a direct response of the skin to an irritant. The most common irritants are soaps, bubble baths (a common cause of severe vaginal pruritus in prepubertal girls), saliva, urine, feces, perspiration, citrus juice, chemicals, and wool. Irritant diaper dermatitis is common in infants, and is differentiated from fungal diaper dermatitis by its sparing of the inguinal folds.