Pediatric emergency medicine trisk 453

to examine their skin when possible. In contrast to adults, infants may develop
blisters and exhibit lesions on the head and face.
The diagnosis is made by scraping involved skin and looking for mites under
the 10× microscope objective ( Fig. 88.5 ). Once an infestation occurs, it usually
takes 1 month for sensitization and pruritus to develop.

FIGURE 88.5 Scabies mite.

Louse Infestation
Three forms of lice infest humans: (i) the head louse, (ii) the body louse, and (iii)
the pubic or crab louse ( Fig. 88.6 ). The major louse infestation in children
involves the scalp and causes pruritus. The female attaches her eggs to the hair
shaft. The egg then hatches, leaving behind numerous nits that resemble dandruff.
Secondary infection can occur from vigorous scratching. Body lice generally
reside in the seams of clothing and lay their eggs there. They go to the body to
feed, particularly the interscapular, shoulder, and waist areas. Red pruritic puncta
that become papular and wheal-like then occur. Pubic lice occur in the genital
area, lower abdomen, axillae, and eyelashes. Transmission is usually venereal.


Blue macules (maculae caeruleae), caused by the bites, are 3 to 15 mm in
diameter and can be seen on the thighs, abdomen, or thorax of infested persons.

FIGURE 88.6 Louse.

Because the body louse resides in clothing, therapy consists mainly of
disinfecting the clothing with steam under pressure. Pediculosis capitis is usually
effectively treated with 1% permethrin or pyrethrin creme rinse though resistance
to this medication is not uncommon. The patient’s hair should be shampooed,
rinsed, and toweled dry. Enough medication to saturate the hair and scalp is
applied. The medication is washed out after 10 minutes. Additionally, benzyl

alcohol–containing products (Ulesfia) and topical ivermectin (Sklice) products
can also be used. Patients with resistant disease may also respond to topical
petrolatum applied to hair and scalp nightly for 1 week as a lice suffocant or
trimethoprim-sulfamethoxazole given orally for 5 to 7 days, which kills the
symbiotic parasite present in the GI tract of head lice. Pediculosis pubis is best
treated with the same permethrin or pyrethrin preparations used for head lice.
Any nits are removed with a fine-toothed comb. The safest treatment for lice in
the eyelashes is the application of Vaseline twice daily for 8 days. The lice stick
to the Vaseline, cannot feed, and die.

Vascular Papules and Nodules
Vascular papules and nodules can be congenital or acquired. Those in infants
generally fall in the category of benign with hemangiomas being most common.


Other vascular nodules, including kaposiform hemangioendotheliomas and
sarcomas, should be considered when vascular papules or nodules feel firm or do
not follow the natural history of infantile or congenital hemangiomas. Acquired
lesions include Spitz nevi and pyogenic granulomas.
Spitz nevus. Spitz nevi appear suddenly between 2 and 13 years of age.
Preferred sites of growth include the cheek, shoulder, and upper extremities ( Fig.
88.7 ). The lesion has a pink to red surface because of numerous dilated blood
vessels. Pressure produces blanching of this pink to red color. The lesions can
reach 1.5 cm in diameter but are completely benign. Pigmented Spitz nevi,
another variant of Spitz nevi, often appear black in the skin rather than pink-red,
and their appearance is often worrisome for malignant melanoma. Because the
histologic appearance of these lesions can be confused easily with a malignant
melanoma, an experienced histopathologist should interpret the findings. Most
clinicians still recommend that Spitz nevi be removed surgically.
Pyogenic granulomas. Pyogenic granulomas ( Fig. 88.8 ) are bright red to

reddish-brown or blue-black pedunculated, vascular papules/nodules ranging
from 0.5 to 2 cm in size that develop rapidly at the site of an injury, such as a cut,
scratch, insect bite, or burn. Pyogenic granulomas occur commonly in children
and young adults, usually on the fingers, face, hands, and forearms.
They bleed easily. Generally, they are asymptomatic. Because spontaneous
disappearance is rare, patients should be referred for definitive treatment,
typically with curettage, excision, electrosurgery, cryosurgery, laser surgery, or
some combination of these various modalities.


FIGURE 88.7 Spitz nevus.

Yellow, Tan, or Brown Papules
Many papules are yellow, tan, or brown. These include the lesions seen in
urticaria pigmentosa (see Chapter 69 Rash: Neonatal ), flat warts, xanthomas,
insect bites, juvenile xanthogranulomas (JXGs) as well as melanocytic nevi.
One way to differentiate the various papules from one another is to scratch
them. If hiving of a scratched lesion (Darier sign) occurs within a short period of
time (3 to 5 minutes), the lesion likely contains mast cells (i.e., a mastocytoma or
urticaria pigmentosa) ( Fig. 88.9 ). Make sure to scratch normal skin to rule out
the presence of dermatographism. The latter condition will produce a falsepositive Darier sign. When no urtication occurs, a biopsy may be helpful. Flat
warts tend to be grouped, are flat topped, and can be autoinoculated in scratch
lines (pseudo-Koebner phenomenon). Lesions characteristic for JXGs are not flat
topped, tend to be singular in number (or when multiple are scattered about), and
do not demonstrate the Koebner phenomenon (recapitulation of the eruption in