The oldest new finding in atopic dermatitis: subclinical miliaria as an origin.

IMPORTANCE: In 1947, Sulzberger and colleagues published a micrograph of a blocked acrosyringium in a patient with atopic dermatitis (AD), believing that it had a large role in the disease process. Lacking appropriate probes, they could not confirm the finding. OBJECTIVE: To confirm the observations by Sulzberger et al on the blockage of sweat ducts in AD in pathologic specimens. DESIGN AND SETTING: Biopsy specimens diagnostic of various inflammatory diseases and with a secondary differential diagnosis of eczema were evaluated at an academic medical center. EXPOSURES: Evidence of ductal obstruction in each specimen was examined following staining with hematoxylin-eosin, periodic acid-Schiff, and Gram stain. MAIN OUTCOMES AND MEASURES: Comparison of biopsy specimens with control specimens and additional controls consisting of noninflamed skin. RESULTS: Using 36 biopsy specimens, this study confirmed the observations by Sulzberger et al on the blockage of sweat ducts in AD. Blocked acrosyringia were noted in each specimen on routine staining with hematoxylin-eosin. The study also confirmed the findings by earlier investigators about the blockage of sweat ducts in miliaria, showing eosinophilic material in the ducts that was positive for periodic acid-Schiff. Previous researchers also observed bacteria in the blockages, and this study demonstrated the same findings in AD, rather than miliaria. CONCLUSION AND RELEVANCE: Subclinical miliaria may be the earliest change in AD and likely initiates the process that causes intense pruritus.

An unusual variant of confluent and reticulated papillomatosis masquerading as tinea versicolor.

BACKGROUND: Confluent and reticulated papillomatosis (CARP), also known as Gougerot-Carteaud syndrome, is a rare disorder. It usually presents as hyperkeratotic brown papules that coalesce into plaques with a reticulated periphery on the central trunk of young adults. Confluent and reticulated papillomatosis is most often clinically confused with tinea versicolor and usually does not respond to therapy with antifungals. Minocycline is the treatment of choice. OBSERVATIONS: Four cases of CARP with the unusual presentation of hypopigmented lesions masquerading as tinea versicolor in dark-skinned (Fitzpatrick skin types IV-V) patients are presented. All cases exhibited characteristic features of CARP on biopsy results and responded to minocycline of several months' duration. Two of the cases were also treated with adjuvant topical tazarotene. CONCLUSIONS: The hypopigmented variant of CARP in dark-skinned patients makes the clinical differentiation from tinea versicolor extremely challenging. Physicians encountering darkly pigmented individuals with hypopigmented plaques unresponsive to antifungals should have a high clinical suspicion for the hypopigmented variant of CARP.