Pediatric emergency medicine trisk 1802 1802

(flat <10 mm), papules (raised <10 mm), patches (flat >10 mm), plaques (raised
>10 mm), nodules (solid lesion 0.5 to 2 cm), pustules (elevation with pus),
abscesses (elevated lesion >10 mm with purulent material), wheals (elevated
lesion with local transient edema), vesicles (elevated lesion <10 mm containing
fluid), and bullae (elevated lesion >10 mm containing fluid). Secondary
descriptors include crust, scale, fissuring, erosions, ulceration, umbilication,
excoriation, atrophy, lichenification, and scar. In addition to these descriptions, it
is also important to understand the distribution of the rash or lesion. Distribution
characteristics include localized, blaschkoid (following lines of embryologic
development), widespread or generalized, and photodistributed (predilection for
sun-exposed areas). Characterizing a rash or lesion using these descriptors
narrows the differential diagnosis significantly. The following sections of this
chapter will divide skin changes by their primary descriptor and then will provide
a framework for adding secondary characteristics to improve diagnosis.

PAPULES
Papules can be quite varied and the following algorithm is used to help
practitioners distinguish between some common papular lesions ( Fig. 88.1 ).

Papules With a Characteristic Appearance
Many conditions can be diagnosed on sight. For example, the experienced eye
can easily distinguish milia from molluscum contagiosum (MC) and warts from
the uncommon xanthoma. Several clues make the process of separating these
entities from one another easier such as color, distribution, and patient
characteristics.

Milia
Milia are 1- to 2-mm firm, white papules. They are produced by retention of
keratinous and sebaceous material in follicular openings. Newborns often have
milia on their face. They frequently disappear by the age of 1 month. Milia can
also arise from skin trauma, and can be seen in scars after burns and in healed

wounds in patients with blistering disorders like epidermolysis bullosa. Persistent
milia may be a manifestation of the oral–facial–digital syndrome, hereditary
hypotrichosis (Marie Unna type), and certain rare ectodermal dysplasias. Because
lesions that are not associated with syndromes often disappear spontaneously,
reassurance is generally warranted, though lesions may be easily removed by
carefully nicking the surface and expressing the keratin. This can be a
simultaneously diagnostic and therapeutic procedure.

Molluscum Contagiosum