Enlarging congenital pigmented plaque. Neurofibroma.
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Biomedical subjects
Publications and source records attributed to Ronald C Hansen.
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Head lice infestations affect millions of people in the United States. Children become infested more often than adults and account for the largest percentage of infestations. Head lice have not been shown to transfer disease, and they are not associated with serious morbidity. The most common effect of lice infestation is pruritus of the scalp with occasional cutaneous infection caused by scratching. Nevertheless, many schools have "no-nit" policies, which require the dismissal of children from school if nits or lice are found. These policies are ineffective in preventing infestations and result in many missed days of school. Lice infestations are most effectively managed with pediculicides. Pyrethroids are the mainstay of over-the-counter products. Prescription pediculicides include OVIDE (malathion) Lotion, 0.5% and lindane (formerly marketed as Kwell). Resistance to pyrethroids due to misuse and overuse has been documented. Lindane resistance also has been reported, and serious safety issues about lindane have been raised by the Food and Drug Administration. Lindane labeling now includes warnings and several restrictions in its use. Malathion is not associated with major systemic safety issues or the development of resistance within the United States. A contributor to pediculicide resistance is misdiagnosis of lice infestations. Survey data reveal frequent misdiagnosis of infestations in children who do not have live lice. Physicians generally are more likely to misdiagnose infestations than nonhealthcare providers. Misdiagnosis contributes to resistance by causing overuse, and consequently overexposure, of pediculicides. These agents should be used only if live lice or viable nits are discovered. Head lice infestations generally do not contribute to health risks for individuals or the public. The most serious consequence is the social cost of missed school days and the associated cost of lost productivity and wages of parents who must care for children sent home from school. Better diagnosis, more appropriate use of pediculicides, and elimination of no-nit policies will improve the overall management of head lice infestations.
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BACKGROUND: Phytophotodermatitis is a phototoxic reaction, occurring in skin exposed to sunlight after contact with plants containing furanocoumarins. Typical reactions are mild, showing erythema with post-inflammatory hyperpigmentation. A 6-year-old boy presented with marked, symmetric, painful erythema and edema of both hands that rapidly developed into dramatic bullae covering the entire dorsum of the hands. The history revealed that the hands had been bathed in lime juice for a prolonged period in the preparation of limeade. OBJECTIVE: This report documents an unusual bullous presentation of phytophotodermatitis resulting from contact with furanocoumarins in local limes. This study was conducted to identify and measure the inciting substances from the rind and pulp of the limes. METHODS: Psoralen, xanthotoxin, bergapten, and isopimpinellin content were measured by gas chromatography and high-pressure liquid chromatography RESULTS: The rind contained 6- to 182-fold concentrations of all furanocoumarins measured when compared with pulp. Bergapten was the most abundant substance in the rind. CONCLUSION: Hydration of the skin during the preparation of limeade combined with increased levels of bergapten in local limes to produce a dramatic bullous reaction. We encourage clinicians to consider the possibility of phytophotodermatitis in severe bullous skin reactions.
Pityriasis rubra pilaris (PRP) is an idiopathic papulosquamous disease that clinically presents with palmoplantar keratoderma and follicular hyperkeratotic papules that coalesce into scaly erythematous plaques. We report a unique case of atypical PRP beginning at 1 year of age with associated severe arthropathy and osteoporosis. We further discuss the clinical and histopathologic aspects of PRP, its possible etiology, and other associated conditions.
Paraneoplastic pemphigus (PNP) is a rare blistering autoimmune disease associated with an underlying neoplasm, mucous membrane erosions, and occasionally bronchiolitis obliterans. Most cases have been reported in adults and the number of childhood cases in the current literature is limited. We describe a young patient with PNP who was initially misdiagnosed as having recurrent Stevens-Johnson syndrome. This patient had an underlying inflammatory myofibroblastic tumor and subsequently developed fatal progressive bronchiolitis obliterans.
An estimated 6 to 12 million head lice infestations occur in the United States annually, with children ages 3 to 12 most likely to be affected. There are significant direct costs associated with treatment and indirect costs due to lost time from school. Anecdotal reports suggest that direct costs of treatment are in the hundreds of millions of dollars annually. Indirect costs are also substantial but more difficult to quantify. Examples of indirect costs include missed days from schools that use a "no nit" policy, lost wages for parents who must stay home with children, and costs of daycare for parents who cannot miss work. Contributors to the expense of treating head lice include misdiagnosis, and, consequently unneeded treatment; treatment failure due to misuse of pediculicides or other agents; and developing resistance, particularly to over-the-counter pyrethroid agents. An overview of direct and indirect costs of infestation are included in this review, along with a discussion of factors that lead to misuse and overuse of pediculicides. More accurate diagnosis of head lice infestation may provide the most effective means of controlling the costs of care and ensuring proper use of pediculicides.