Great Cases in Pediatric Dermatology
The session 'Great cases in pediatric dermatology' was presented by Richard J Antaya from Yale University (CT, USA). Dr Antaya reviewed many great cases, but we herein include the treatment discussion of these interesting cases, reviewing newer therapeutics in pediatric dermatology.
Impetigo contagiosa is caused by both S. aureus and Streptococcus pyogenes. It occurs in humid climates and the summer months. It is secondary to trauma and insect bites, and is characterized by discrete, thin-walled vesicles that rapidly become pustular and then rupture. Treatment includes oral antibiotics such as cephalexin, dicloxacillin, amoxicillin with clavulanic acid, erythromycin or cefaclor. Topical treatments include mupirocin, retapamulin 1% ointment, as well as soaking the crusts off. Bullous impetigo is a variant that is always caused by S. aureus. Its epidermolytic toxin cleaves the stratum granulosum, which is the same toxin implicated in staphylococcal scalded skin syndrome. This causes large fragile bullae, which, when ruptured, leave circinate or crusted lesions. Treatment includes oral antistaphylococcal antibiotics.
Tinea corporis is a cutaneous fungal infection of the superficial epidermis. It can be diagnosed with a potassium hydroxide preparation on a slide of scraped scale from a lesion stained with chlorazol black E fungal stain. It can be treated with topical antifungal medications. When tinea capitis is present, deep tender boggy plaques exuding pus, known as a kerion, can develop. Kerion may be followed by scarring and permanent alopecia in the areas of inflammation and suppuration. Treatment is accomplished with systemic steroids such as prednisone 1–2 mg/kg/day for 5 days, along with a systemic antifungal such as griseofulvin. Bacteria can be cultured and oral antibiotics may be needed.
Granuloma annulare presents as small firm papules that form an annular plaque. They can be skin colored, dusky or violacious. There is no scale and the inflammation is concentrated in the dermis. It is common to see lesions in the acral locations. There can be associated necrobiosis or destruction of the dermal collagen, or deep subcutaneous nodules. Lesions can be localized or generalized. Since most of the lesions are asymptomatic and spontaneous resolution is noted to occur, no treatment is required.
Pediculosis capitis, or head lice, is frequently encountered in the pediatric patient. Combing is four-times more effective and two-times faster than visual inspection at detecting head lice. Combing of the hair should be carried out with a nit comb with teeth spacing of 0.2–0.3 mm, and combing wet hair may be more effective. Combing should be done systematically at least twice, and the comb examined after each pass.[32] First-line treatments include pyrethrins 0.3% or permethrin 1% cream. It should be applied to the scalp for 10 min and then rinsed out and reapplied 8–10 days later. An examination for live lice should be repeated in 8–10 days. If live lice persist after two treatments, malathion 0.5% lotion can be tried. Side effects include scalp irritations, dandruff and conjunctivitis, and it is flammable until dried. 5% benzyl alcohol lotion was recently approved for the treatment of head lice in patients greater than 6 months of age. It kills the lice by asphyxiation without potential neurotoxic side effects. It should be avoided in premature infants because of serious respiratory-, heart- or brain-related adverse effects.
Allergic contact dermatitis commonly occurs in the pediatric setting. Acute lesions are erythematous with vesiculation and oozing, while chronic lesions are dry and lichenified. The most common offenders include toxicodendrons such as poison ivy, oak or sumac, as well as metals (such as nickel), neomycin, preservatives, fragrances, chromates and rubbers in shoes and dye from black henna tattoos. A quick test for nickel-containing products is the dimethylglyoxime test. There are even reported cases of an allergic contact dermatitis to nickel contained in cell phones. The most common sites on the cell phone that contain nickel include the menu buttons, decorative logos and metallic frames around the screens.
Pilomatricoma or calcifying epithelioma of Malherbe is a benign tumor derived from hair matrix cells. It usually occurs as a single lesion most commonly found on the face, neck or proximal upper extremity. It is usually rock-hard with a bluish coloration. It accounts for 10% of all skin nodules encountered in children. Spontaneous regression is not reported and surgical excision is required with a recurrence rate of less than 5%. Familial occurrences are reported in 13.3%. Multiple lesions occur in 26.7% and are seen in myotonic dystrophy Steinert syndrome, Rubinstein–Taybi syndrome or Gardner syndrome.
Hemangiomas are encountered in the pediatric setting and a novel approach to treating them is with propranolol. In a study of 31 infants with severe or disfiguring infantile hemangiomas, propranolol was used at 2–3 mg/kg/day for a duration ranging from 2 to 10 months. 24 h after initiation of treatment, the hemangiomas changed from intense red to purple, and also softened. All continued to improve until flat. It is hypothesized that propranolol works initially by vasoconstriction and then later by the inhibition of Raf/MAPK activation, which stimulates cell proliferation. It may also trigger apoptosis of capillary endothelial cells and increase interstitial fibrosis.[33] Before treatment, baseline laboratory assessments including blood glucose, electrocardiogram and echocardiogram should be performed. Exclusion criteria included bronchospasm, cardiac disease and CNS anomalies. The initial dose is 0.5 mg/kg/day divided twice- to three-times per day and then increased to 2 mg/kg/day divided twice- to three-times per day over 2 days to 3 weeks. The patients should be monitored initially in a hospital setting for 24–72 h, with blood pressure, heart rate, glucose and temperature monitoring 1 h after dose. Bronchospasm should be watched for and the dose should be held for a heart rate less than 100 beats per minute. Parents should be told to observe the child for lethargy, poor feeding or bronchospasm.