Langerhans Cell Histiocytosis
A previously healthy 52-year-old man had been using an antidandruff shampoo and a topical corticosteroid for a chronic scalp eruption that had been diagnosed as seborrheic dermatitis. Because the condition had not responded to this regimen, a scalp biopsy was performed; the findings were consistent with seborrheic dermatitis.
The patient had no family history of skin disorders. He smoked 1 to 2 packs of cigarettes a day and worked in a car-wrecking yard, salvaging car parts. The patient was afebrile, and his weight was stable. He denied picking or scratching his skin.
The scalp was studded with erythematous, firm, nonfollicular papules and erosive plaques covered with a yellowish exudate (A). Erosive, foul-smelling plaques associated with yellowish exudate were seen in the perianal (B), inguinal, and axillary areas (C), and numerous asymptomatic erythematous papules were noted on the chest (D). There were no palpable peripheral lymph nodes, hepatosplenomegaly, or joint effusions.
Multiple skin cultures from the scalp, perianal, axillary, and inguinal areas grew out a mixed flora of Staphylococcus aureus, Escherichia coli, Enterobacter cloacae, Pseudomonas, and Klebsiella. A 3-week course of oral ciprofloxacin and cephalexin was prescribed, and the patient was instructed to wash the affected areas with a diluted solution of chlorhexidine gluconate followed by application of mupirocin ointment 3 times a day.
At follow-up, the patient's condition had not improved; biopsies were performed in the scalp, chest, and axillary areas. Review of systems was significant for a chronic, nonproductive cough.
Drs Patricia Wong and Sabine Kohler of Stanford University Medical Center in California report that examination of the skin specimens confirmed Langerhans cell histiocytosis, or histiocytosis X, a disease that predominantly affects infants and children but, infrequently, may develop in adults. The differential for eroded plaques in a seborrheic distribution (scalp and flexural areas) also includes severe inflammatory seborrheic dermatitis with secondary bacterial infection; however, the findings in this patient are markedly disproportionate to the expected findings in seborrheic dermatitis. Moreover, seborrheic dermatitis is generally not an erosive dermatitis.
Hailey-Hailey disease, or benign familial chronic pemphigus, is also in the differential. This is an autosomal dominant disorder, but only about 70% of patients with the disease have a positive family history. Consider, too, hidradenitis suppurativa, which can present in flexural areas and the scalp. Multiple inflamed cysts, draining sinuses, and scarring are the usual manifestations.
In adults, Langerhans cell histiocytosis typically presents with pulmonary manifestations, although bone, skin, and CNS involvement have been observed. The disease is a proliferative, neoplastic disorder of Langerhans cells. The disease course is variable and unpredictable; it can be acute, subacute, or chronic and may be stable, progressive, or regress spontaneously.
Low-power microscopic examination shows a spongiotic dermatitis; the epidermis is multifocally infiltrated by Langerhans cells (E, arrow) that focally collect in microabscesses. High-power examination reveals kidney-shaped nuclei and abundant, slightly eosinophilic cytoplasm (F). On immunophenotyping, Langerhans cells react with antibodies against S100 protein and CD1a, the latter being the more specific marker (G).
The prognosis depends on patient age and the extent of organ involvement. Persons who have only isolated bone lesions or skin disease have an excellent prognosis; those with skin involvement and disseminated disease have a poor prognosis. The mortality rate is 50% or greater for patients with disseminated disease who are younger than 2 years or older than 60 years.
A variety of therapies, including corticosteroid injections, surgery, radiation, and chemotherapeutic agents, have been used for Langerhans cell histiocytosis. Etoposide was given to this patient because of the multisystem—lung, bone, and skin—involvement. His initial response was good; he was lost to follow-up. This patient's oncologist comments that because of the potential leukemogenic risk of etoposide, he most likely would now use methotrexate instead.