Epidermal multinucleated keratinocytes: a histopathologic clue to dermatitis artefacta

Histopathological and Immunohistochemical Characteristics of Measles Exanthema: A Study of a Series of 13 Adult Cases and Review of the Literature

Despite available vaccination, measles is one of the leading causes of death among young children in developing countries. In clinical practice, the spectrum of differential diagnoses of morbilliform exanthemas associated with fever is wide, and it can be hard to differentiate from other infectious eruptions, especially in adults or in atypical courses in immunocompromised patients. The goal of our study was to identify characteristic histomorphological and immunohistochemical patterns of measles exanthema through the study of 13 skin biopsy specimens obtained from 13 patients with this disease and a review of cases in the literature. Histopathological features of measles exanthema are quite distinctive and characterized by a combination of multinucleated keratinocytes, and individual and clustered necrotic keratinocytes in the epidermis with pronounced folliculosebaceous as well as acrosyringeal involvement. Immunohistochemical staining of skin biopsies with anti-measles virus (MeV) nucleoprotein and anti-MeV phosphoprotein can be of great value in confirming the diagnosis of measles. Both methods can serve as quick additional diagnostic tools for prompt implementation of quarantine measures and for providing medical assistance, even in patients in whom the clinician did not consider measles as a differential diagnosis of the rash due to the rarity of the disease in a putatively vaccinated community.

[Bullous dermatitis with multinucleated keratinocytes in dermatitis artefacta: A case report]

We report the case of a 13-year-old young lady with a one year reccuring bullous dermatitis history for which the diagnostic hypothesis of dermatitis arterfacta was made. This hypothesis was made by the pathologist, without it being suggested by the dermatologist, after observing singular histological lesions coresponding to a cutaneous blister associated with epidermic necrosis with multinucleated keratinocytes. When dermatitis artefacta is suspected, a biopsy is usually conducted to rule out differential diagnosis such as auto-immmune dermatitis when there is a blister. Confession from patients is rarely obtained. Therefore, having positive histogical clues for dermatitis artefacta would be of a great use to help making the diagnosis in difficult cases.

Dermatitis artefacta

Dermatitis artefacta, also known as factitial dermatitis, is a condition whereby self-induced skin damage is the means used to satisfy a conscious or unconscious desire to assume the sick role. It is particularly common in women and in those with an underlying psychiatric diagnosis or external stress. The diagnosis is one of exclusion, and it is often difficult to confirm, with patients rarely admitting their role in the creation of their lesions. Treatment can be challenging, and management should adopt a multidisciplinary team approach composed of dermatologists and mental health professionals. We present a literature review of dermatitis artefacta, highlighted by a case report of a patient with bilateral ulcerations to the legs, which after thorough investigation represented dermatitis artefacta.

Factitious Dermatitis Due to Thermal Burn With Histologic Features Simulating Fixed Drug Eruption

Factitious dermatitis (FD) (dermatitis artefacta) is rare and often difficult to diagnose because of conflicting history and nonspecific clinical and histologic findings. It can present with varied clinical features including geometric ulcers, erosions, and less commonly bullae secondary to external trauma from chemicals, electric burns, heat, and suction. Herein, we describe a case of bullous FD due to thermal burn with histologic features demonstrating overlap with fixed drug eruption. Histopathology demonstrated a subepidermal blister with epidermal necrosis along with pigment incontinence and dermal eosinophils and neutrophils. Although these features, and the clinician's impression, were suggestive of fixed drug eruption, several morphologic findings allowed accurate diagnosis of FD: sharp demarcation of necrotic keratinocytes from adjacent uninvolved epidermis, elongated keratinocytes reminiscent of thermal or electrical artifact, and multinucleated keratinocytes. Although FD is often considered a diagnosis of exclusion, these clues may help dermatopathologists distinguish this entity from inflammatory dermatoses.