Pediatric emergency medicine trisk 455

FIGURE 88.12 Lichen nitidus.

One can reassure parents that three-fourths of lesions clear spontaneously
within a 2-year period. Recurrences are common until children outgrow this
tendency.


FIGURE 88.13 Granuloma annulare.

Lupus
Neonatal lupus and systemic lupus can sometimes be composed of annular
plaques. Lupus has a varied appearance depending on type and whether it is skin
limited or systemic. For more discussion please see Chapter 69 Rash: Neonatal
for discussion of neonatal lupus and Chapter 67 Rash: Vesiculobullous for
discussion of bullous lupus.


NODULES
Nodules in the skin can be difficult to diagnose and many require a skin biopsy.
There are a few inflammatory conditions of the skin that are characteristically
nodules and should not be missed.

Panniculitis
Erythema Nodosum
Erythema nodosum seems to be a hypersensitivity reaction leading to
inflammation of the subcutaneous fat and may be related to infection
(streptococci, tuberculosis, coccidioidomycosis, histoplasmosis), inflammatory
bowel disease, sarcoidosis, and medications (e.g., oral contraceptives). The exact
immunologic mechanism has not been clarified. The entity occurs predominantly
in adolescents during the spring and fall. Women are affected more often than
men.

The lesions of erythema nodosum appear as deep, tender, erythematous
nodules, or plaques on the extensor surfaces of the extremities. The sedimentation
rate is generally elevated and usually returns to normal with disappearance of the
eruption, unless an underlying disease is present. The reaction usually lasts 3 to 6
weeks. Treatment should be directed toward the cause when and if established;
otherwise, it is symptomatic (nonsteroidal anti-inflammatory drugs and
antihistamines). Corticosteroids should be avoided, except in severe cases after an
underlying infection has been ruled out.
Cold Panniculitis
Cold panniculitis is caused by cold injury to fat. During the cold of winter, infants
and some older children develop red, indurated nodules and plaques on exposed
skin, especially on the face. The subcutaneous fat in infants and some children
solidifies more readily at a higher temperature than that of an adult because of the
relatively greater concentration of saturated fats. Infants who hold ice chips or
popsicles in their mouths are also susceptible to this phenomenon (“popsicle
panniculitis”). The lesions gradually soften and return to normal over 1 or more
weeks. Treatment is unnecessary.

Generalized Macules and Papules/Morbilliform Eruptions
The causes of morbilliform eruptions rashes are diverse ( Table 88.1 ) and range
from benign to life-threatening ( Table 88.2 ). Common causes include viral
exanthems and drug reactions. The diagnostic approach to these disorders is
based on the presence or absence of fever, characteristic clinical appearance,


location, chronicity, and medication history. Some of these conditions have very
characteristic clinical appearances ( Table 88.3 ); however, manifestations of
these illnesses can be sufficiently variable that a proportion of the cases are
difficult to diagnose.