The diagnosis of a pustular dermatosis occurring during the first months of life is usually based on clinical findings. However, some cases may require simple investigations including microscopic examination of pustular content, cultures, and skin biopsies. The main benign transient neonatal types of pustulosis include erythema toxicum neonatorum, infantile acropustulosis, transient neonatal pustular melanosis, and neonatal acne. The most common causes of infectious pustular skin lesions include bacterial infections, which may be initially localized (Staphylococcus aureus) or septicemic (with Listeria monocytogenes as the leading causitive agent); viral infections (herpes simplex, varicella-zoster, and cytomegalovirus infections); fungal infections (candidiasis); or parasitic disorders (scabies). The main objective of this article is to propose a systematic approach to pustular eruptions in the neonate. The need for investigating every neonate with pustules for an infectious disease is emphasized. The Tzanck smear, the Gram's stain, and a potassium hydroxide preparation are the most important quick diagnostic tests. The Tzanck smear is a very easy, rapid, and sensitive test for detection of a herpetic infection (multinucleated giant cells) as well as noninfectious pustular eruptions (eosinophils, neutrophils). Therefore the Tzanck smear should be the first test performed. Moreover, a Gram's stain and potassium hydroxide preparation should be performed in cases of neonatal pustular disorders to detect bacterial and fungal infections. The goal of this diagnostic approach is to spare a healthy neonate with a benign transient condition an invasive evaluation for sepsis, potentially harmful antibiotic therapy, and prolonged hospitalization, with its own inherent morbidity.
Between 1964 and 1994, at least 52 patients with cutaneous adverse effects of vitamin K have been described in the European and North American literature. A review of the details of these patients is given and 2 new cases reported. Adverse effects are seen not only in patients with liver-function disturbances but also in patients without liver diseases, and occur mostly after intramuscular or subcutaneous administration of vitamin K1, independent of the total dose. Patch and intracutaneous tests often give positive reactions. The mechanism of action is probably in many patients a delayed-type hypersensitivity reaction.
The Tzanck test and electron microscopy with the technique of colloidal gold labelling in varicella-zoster virus (VZV) infections were compared with virus isolation in 54 patients with clinically suspected varicella or herpes zoster infection. The Tzanck test and direct electron microscopy can determine whether or not an eruption is herpetic but cannot distinguish between herpes simplex virus (HSV) and VZV infection. However, colloidal gold immuno-electron microscopy, using monoclonal antibodies against HSV and anti-VZV IgG, can distinguish between these two herpes viruses. This achieves the same specificity as virus isolation followed by virus neutralization or virus typing using immunofluorescence techniques. The Tzanck test was positive in 91%, virus isolation, under optimal conditions of sampling and transportation, in 80%, direct electron microscopy (negative staining) in 80%, and colloidal gold immuno-electron microscopy after a virus concentration procedure in 95% of the cases. The colloidal gold technique offers a rapid diagnosis in patients with suspected VZV infection.
The Tzanck smear, introduced by the Frenchman Tzanck, has been used for many years in the diagnosis of bullous and vesicular dermatoses especially herpes simplex, herpes zoster and varicella. Also, in the vesicular dermatoses of newborns and immunocompromised patients it is an important diagnostic aid. The Tzanck smear is easy to perform, simple, reliable (if one is experienced) and inexpensive. A quick staining can be done by Hemacolor or Diff-Quik within one minute. The Tzanck smear is certainly useful and very reliable in the diagnosis of herpes simplex and varicella-zoster infections if obtained in the vesicular stage. The sensitivity of the Tzanck smear exceeds 80%, and the specificity 90% when the investigators are experienced. A positive Tzanck smear is an especially reliable and useful diagnostic aid. However, a disadvantage is that the smear cannot differentiate between herpes simplex virus or varicella-zoster virus infections. The Tzanck smear, although old and simple, remains an important aid in the diagnosis of vesicular, pustular and bullous diseases, in particular herpes. Cytology will, however, never replace culturing or histopathology.
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