Dermatitis can present with a variety of physical examination findings ranging from exuberant oozing to dry scale. These findings represent the acute and chronic inflammation that defines a variety of dermatitides and eczematous conditions. Intense itching that accompanies these conditions can lead to overlying excoriations and eventually thickening of the skin known as lichenification . Ultimately, constant itching and a poor epidermal barrier predispose patients with these eczematous conditions to repeated skin infections from bacteria and viruses, which can present with pustules, vesicles, crusting, erosions, or painful nodules. Screening for signs of such infections is an important part of the physical examination for all patients with dermatitis, especially those with any underlying immunodeficiency.
Although most cases will not require a skin biopsy for a diagnosis, the spongiosis of acute dermatitis or the acanthosis of the epidermis seen in chronic dermatitis can be confirmatory in scenarios wherein other diagnoses that affect the epidermis are being considered, such as nutritional deficiencies, graft-versus-host disease, or psoriasis.
The anatomic location of atopic dermatitis (AD) can vary depending on age. Infantile AD tends to affect the cheeks and can have impressive overlying exudation and crusting even in the absence of infection. In infants, AD can also be quite widespread with predilections for extensor surfaces and notable sparing of the diaper region and nose, the so-called headlight sign. Childhood AD may be more localized to the flexors and can begin to take on a more lichenified appearance. Many people with AD will outgrow a more widespread dermatitis, but may have chronic hand dermatitis or other more localized flares of their AD. Associated features of AD found on physical examination include Dennie-Morgan lines (accentuated folds of the lower eyelids), keratosis pilaris, general xerosis, follicular accentuation, and signs of atopy such as hyperpigmentation around the eyes known as allergic shiners .
Other forms of eczema may take on different patterns on the body, including the coin-shaped, scaly, and exudative plaques of nummular eczema or the diffuse, dry, and cracked appearance of xerotic eczema (eczema craquele). Even in patients without a history of AD, localized forms of eczema may arise on the eyelids or nipples, or on the hands as vesiculobullous hand eczema (pompholyx). Finally, some forms of immunodeficiency disorders can present with relatively nonspecific exfoliative erythroderma, as in severe combined immunodeficiency (SCID), or an atopic dermatitis-like eruption, as in hyper–immunoglobulinemia E (IgE) syndrome, Wiskott-Aldrich syndrome (WAS), or DiGeorge syndrome. In these cases, the astute clinician will observe distinctive clinical findings such as the pustular eruption of hyper-IgE syndrome, dysmorphisms of DiGeorge syndrome, or petechiae within the dermatitis of patients with WAS. This portion of the atlas will highlight the range of clinical findings seen in patients with atopic dermatitis and other forms of eczema, along with rarer findings seen in patients with immunodeficiency syndromes.