Chapter 58 Pediatric dermatology
2. Name the papulopustular facial eruption often associated with inappropriate topical steroid use.
Periorificial dermatitis is a perioral, periorbital, and perinasal, erythematous, slightly scaling papulopustular eruption seen most commonly in preschool children. Treatment of this condition is the discontinuation of topical steroids and the use of the same oral or topical antibiotics that are used for acne vulgaris. Tetracycline and derivatives should not be used in children under 8 years of age.
6. Red, scaly, itchy, weight-bearing skin surfaces of the feet in children are usually not due to tinea pedis, but to what?
7. Plant dermatitis, such as poison ivy, is the most prevalent cause of allergic contact dermatitis in children. What are some others?
8. One- to 2-mm keratotic papules located on the face, outer upper arms, and thighs are frequently misdiagnosed as folliculitis. What are they really?
11. How is tinea capitis treated?
Oral griseofulvin is the treatment of choice. Oral terbinafine and itraconazole are also used. Topical antifungals have no role in the treatment of tinea capitis. Some authorities recommend twice-weekly shampooing with 2% selenium sulfide or ketoconazole shampoos as a useful adjunctive therapy to griseofulvin, because it is sporicidal and may prevent spread to other children and family members.
Trovato MJ, Schwartz RA, Janniger CK: Tinea capitis: current concepts in clinical practice, Cutis 77:93–99, 2006.
12. What is the hypersensitivity reaction to tinea capitis that is commonly mistaken for a bacterial superinfection?
14. What percentage of children with psoriasis will have guttate psoriasis?
15. Describe the rash associated with childhood dermatomyositis.
A malar photosensitive rash, with red flat-topped papules on the knuckles (Gottron’s papules) and edematous plaques on the elbows and knees, is often seen in childhood dermatomyositis (Fig. 58-2). Unlike adult disease, childhood dermatomyositis is not related to internal malignancies.
16. A child’s mother tells you that the rash started at one end of her child’s extremity and has now progressed to form a line the entire length of the limb. What is your diagnosis?
Lichen striatus. It occurs in children aged 2 to 12 years and characteristically begins at one end of an extremity and slowly progresses the length of the extremity. The nature of the rash may vary from hypopigmented and macular to thickened and scaly (Fig. 58-3). No treatment is effective, and the lesions disappear spontaneously. The pathogenesis of this unusual dermatosis is unknown.
18. If it is not sunburn but a photosensitive eruption is suspected, what is it?
Polymorphous light eruption (Fig. 58-4), erythropoietic protoporphyria, and systemic lupus erythematosus are the three most common causes of a nonsunburn photoeruption in childhood.
20. Which disease should be considered in a child with easy blistering of the skin?
A child with skin that blisters with minimal trauma should be evaluated for one of the mechanobullous diseases, also known as epidermolysis bullosa. There are multiple subtypes, but clinically there are three important variants: epidermal and junctional, which are both nonscarring, and dermal, which is scarring (see Chapter 6).
21. Two common nodules are seen in childhood. Name them.
Epithelial (epidermoid) cysts comprise 60% of the nodules seen in children, and pilomatricomas (Fig. 58-6) account for another 10%. The other 30% of nodules in children are caused by many relatively uncommon problems.
22. Crusted purpuric papules and a scaly seborrheic-like eruption in the scalp and groin are seen in what serious disease of childhood?
This constellation of findings should suggest Langerhans cell histiocytosis (formerly called histiocytosis-X) (Fig. 58-7). The disease can vary from a mild cutaneous-only eruption to a severe, life-threatening, systemic disease. Traditionally, this disease has been treated by pediatric oncologists.
Figure 58-2. Dermatomyositis. Note Gottron’s papules, which present as purple papules over the finger joints.
Figure 58-3. Lichen striatus presenting as hyperkeratotic linear plaque on the lower leg of a child.
Figure 58-7. Langerhans cell histiocytosis demonstrating erythematous scale and crusted papule in the groin of a child.
Windebank K, Nanduri V: Langerhans cell histiocytosis, Arch Dis Child 94:904–908, 2009.
23. Name the skin nodule in childhood that is characterized by frequent bleeding.
Pyogenic granulomas (lobular capillary hemangiomas) are <1-cm, dull-red, firm nodules that bleed easily when traumatized. They are neither pyogenic nor granulomatous, but are thought to be the result of excessive blood vessel formation in response to minor trauma. Treatment is either pulsed dye laser or curettage followed by electrocautery.
Lin RL, Janniger CK: Pyogenic granuloma, Cutis 74:229–233, 2004.
24. Flesh-colored to brown macules and papules that hive when stroked (Darier’s sign) are diagnostic of what eruption?
Mastocytosis. Mastocytosis is due to an excess of normal-appearing mast cells in the skin. There are four forms, with solitary mastocytomas and urticaria pigmentosa (Fig. 58-8) being the most common. Diffuse cutaneous mastocytosis and telangiectasia macularis eruptival perstans are the other types.
25. The onset of annular erythema in sun-exposed areas in children less than 6 months of age should make you want to do what test on the infant’s mother?
This eruption is consistent with neonatal lupus erythematosus and is associated with maternal autoantibodies to SS-A/Ro and/or SS-B/La. The mothers are often asymptomatic or have only mild symptoms of Sjögren’s syndrome at the time of delivery. Neonatal lupus can also cause complete heart block.
Lee LA: The clinical spectrum of neonatal lupus, Arch Dermatol Res 30:107–110, 2009.
26. Which is the most common type of vasculitis seen in children?
Henoch-Schönlein or anaphylactoid purpura. This type of vasculitis frequently follows upper respiratory tract infections and is characterized by the finding of IgA depositions in the blood vessels. The disease may affect only skin, but arthritis, gastrointestinal pain and bleeding, and kidney and central nervous system (CNS) disease may occur.
29. List the three most common types of acquired circumscribed hair loss in children.
Alopecia areata, tinea capitis, and trichotillomania. Alopecia areata is thought to be an autoimmune disorder, whereas tinea capitis is a fungal infection of the scalp hairs. Trichotillomania is self-inflicted and shows an irregular pattern of hair loss. Scalp appearance is normal in alopecia areata and scaly in tinea capitis; trichotillomania is associated with petechiae.
30. What are the two most common causes of congenital circumscribed hair loss?
Sebaceus nevus (organoid nevus) and aplasia cutis congenita. Sebaceus nevus is a birthmark of sebaceous glands. It presents as a yellow-orange plaque on the scalp, face, and upper chest. Aplasia cutis congenita is a localized absence of skin. It presents as either an open ulceration or a scar. The scalp is the most common location, but areas of aplasia cutis congenita may be seen anywhere on the body. When either of these lesions is present on the scalp, no hair grows in the affected area.
31. What should you think of in a 3-year-old who has never required a haircut?
Such a child is likely to have either a hair shaft defect or a type of ectodermal dysplasia. Hair shaft defects are structural abnormalities that cause hair to be fragile and easily breakable. The defects can be recognized by microscopic evaluation. The ectodermal dysplasias may affect not only hair but also nails, teeth, and sweat glands.
32. What are the cutaneous findings seen in tuberous sclerosis complex?
33. How many café-au-lait macules must be present on a child to make you worry about neurofibromatosis type 1 (von Recklinghausen’s disease)?
34. What is a Mongolian spot (middermal melanocytosis)?
This is a blue-black macule found in up to 90% of black and Asian newborns. The most common location is the sacral region (Fig. 58-9), but they may be seen on any portion of the body.
35. What are congenital pigmented nevi, and who cares?
Congenital pigmented nevi (see Fig. 58-9) are developmental errors of pigment cells (melanocytes). They should be defined as small (<1.5 cm), medium (1.5 to 20 cm), and large (>20 cm) in their largest diameter at birth. Some authorities define large as covering >5% of the body surface. Small/medium congenital pigmented nevi are quite common (1/100), whereas large congenital pigmented nevi are rare (1/20,000). The controversy surrounding these lesions concerns their malignant potential. Lifetime risk for the development of melanoma in large congenital pigmented nevi is 1% to 2%.
36. Child abuse is often incorrectly suspected when a young girl presents with what disease?
Lichen sclerosus. This problem frequently presents as hypopigmented perianal and perivaginal plaques. The epidermis is thinned, and the dermis is sclerotic. Purpura, telangiectasias, ulcerations, and excoriations may also be present. Itching and burning of the genital area are often the complaints that bring the child to the physician. Treatment is with superpotent topical steroids.
Smith SD, Fischer G: Paediatric vulval lichen sclerosus, Australas J Dermatol 50:243–248, 2009.
