Annular lichenoid diseases.

Annular lichenoid diseases encompass a diverse range of pathologies that present as circular, raised, or flat lesions that may vary in size and number. Examples include annular lichenoid dermatitis of youth, annular lichen planus, erythema dyschromicum perstans, erythema multiforme, fixed drug eruption, lichen sclerosus, neonatal lupus, porokeratosis, subacute cutaneous lupus erythematosus, and lichenoid syphilis. Clinical morphology and histopathology can differentiate these entities.

Linezolid as a treatment option for cutaneous non-tuberculous mycobacterial infections.

Cutaneous non-tuberculous mycobacterial (NTM) infections have rapidly increased in incidence in recent years. Currently there is no standard treatment and the variable and nonspecific ways in which cutaneous NTM infection presents makes it a therapeutic and diagnostic challenge. We describe a 67-year-old immunocompetent woman with cutaneous NTM infection after she recently underwent a root canal procedure. Although the species was not identified and she was unable to tolerate multiple antibiotics, she ultimately responded well to three months of treatment with linezolid. Given that cutaneous NTM infection can present in immunocompetent patients and that the incidence is rising, it is important for clinicians to maintain a high index of clinical suspicion, especially in patients with a recent history of surgery, trauma, or cosmetic procedures. Linezolid has coverage against non-tuberculous mycobacteria and is an effective therapeutic option for cutaneous NTM cases in which identification to the species level is not possible or when adverse effects limit therapeutic options.

Olanzapine-Induced Hyponatremia Presenting with Seizure Requiring Intensive Care Unit Admission.

Rapid-onset hyponatremia is a rare, but potential, complication of olanzapine treatment. Hyponatremia, secondary to atypical antipsychotic use, has been reported in many case reports and is thought to be associated with a syndrome of inappropriate anti-diuretic hormone secretion (SIADH). Psychogenic polydipsia is a separate cause of hyponatremia, which is also seen in the psychiatric population, particularly in schizophrenia, and must be differentiated from SIADH. We report a case of sudden-onset hyponatremia resulting in seizure onset necessitating intensive care unit admission in a patient taking olanzapine during hospitalization in a psychiatric unit. Clinicians should be aware of the association between olanzapine and hyponatremia secondary to SIADH or psychogenic polydipsia. As in our case, the patient status may decline rapidly, resulting in seizure onset. Physicians should actively monitor patients taking antipsychotics for changes in serum sodium levels.

Interdigital Tinea Nigra.

Tinea nigra is an uncommon superficial dermatomycosis precipitated by Hortaea werneckii, a halophilic and halothermic yeast-like fungus capable of producing a melanin-like substance. This pathogen infiltrates the stratum corneum in the setting of microtrauma and produces an asymptomatic brown to black macule or patch that appears similarly to melanocytic nevi or melanoma. We present a case of a 52-year-old woman who presented to clinic several months after developing a painless, nonpruritic dark brown patch in her left foot inside the fourth toe web. The coloration and location of this lesion would typically prompt biopsy; however, Wood's lamp examination and potassium hydroxide (KOH) preparation were pursued first and demonstrated evidence of infection by H. werneckii. The patient was treated with topical clotrimazole cream and miconazole powder for one month, and her lesions cleared completely. Her lesions did not recur at her three-month follow-up appointment.

The Great Masquerader: Syphilis Mimicking Papilledema and Traction Alopecia.

Syphilis is often referred to as "the great masquerader," as it may present with a wide array of clinical symptoms and may mimic a variety of other diseases making diagnosis challenging. We report the case of a young, married woman who presented with a one-month history of significant hair loss, unintentional weight loss, blurred vision, and intermittent headaches. In addition, she endorsed positional dizziness and intermittent arthralgias. Physical exam was only remarkable for a non-scarring alopecia over the frontal marginal hairline and optic disc edema on fundoscopic exam. Laboratory tests were largely unremarkable except for a rapid plasma reagin titer of 1:128 and a positive confirmatory treponemal test. Cerebrospinal fluid analysis showed lymphocytic pleocytosis and negative Venereal Disease Research Laboratory test. Opening pressure was 15 cm H2O twice, ruling out papilledema. She was treated with 4 million units of intravenous penicillin every four hours for 14 days, and her symptoms improved. A diagnosis of syphilis should remain high on the differential diagnosis in patients with unexplained hair loss or ocular abnormalities.

Acrokeratoelastoidosis: is there an association between asthma and sporadic cases in children?

Acrokeratoelastoidosis (AKE) is a rare, benign papular keratoderma that presents as keratotic papules on the lateral margins of the palms and soles. It is most commonly inherited in an autosomal dominant fashion, although sporadic cases are also described. We present a sporadic case of AKE in an 11-year-old girl with a past medical history significant for asthma. On literature review, we found three other cases presenting in children with a past medical history of asthma. We suggest a possible association between asthma and sporadic cases of AKE in children. Current understanding of the pathophysiology of AKE and its associated risk factors is limited and no effective treatment exists. Awareness of a possible association with asthma and atopy, careful history recording in young patients presenting with sporadic cases of AKE, and further research may help to delineate the likelihood of an association between AKE and asthma or atopy. Developing a better understanding of the associated factors that may contribute to the disease process may help guide more effective, targeted treatments in the future.

Palmoplantar eruption in a patient with mercury poisoning.

Mercury poisoning is a rare event that can present with a variety of nonspecific systemic symptoms, making it difficult to diagnose. Dermatologic manifestations of mercury exposure may be variable and include pink disease (acrodynia), mercury exanthem, contact dermatitis, and cutaneous granulomas. We present the case of an 18-year-old woman with a palmoplantar eruption associated with tachycardia, hyperhidrosis, myalgia, paresthesia, and muscle fasciculations. Physical examination demonstrated poorly demarcated pink macules coalescing into patches on the left palm, right wrist, and soles. A punch biopsy was nonspecific, showing acanthosis and orthokeratosis with mild inflammation. Elevated urine and serum mercury levels confirmed a diagnosis of mercury poisoning. This case highlights the importance of consideration of mercury poisoning in the differential diagnosis for acral eruptions, especially in the presence of systemic symptoms and known risk factors.

(+)-Echinobetaine B: isolation, structure elucidation, synthesis and preliminary SAR studies on a new nematocidal betaine from a southern Australian marine sponge, Echinodictyum sp.

The principle nematocidal agent present in a southern Australian marine sponge of the genus Echinodictyum has been isolated and identified as the novel betaine (+)-echinobetaine B (6), and the structure assigned by spectroscopic analysis has been confirmed by total synthesis. Preliminary SAR conclusions are drawn from analysis of synthetic intermediates and the known marine metabolites zooanemonin (12) and norzooanemonin (13), and the new sponge metabolite norzooanemonin methyl ester (14). The latter compound is reported for the first time from a selection of Australian sponges, including an Axinyssa sp., a Niphates sp., an Axinella sp. and a Ptilocaulis sp.