[Differential diagnosis of febrile exanthema]

Febrile exanthema (FE) is an extremely polymorphous clinical entity, frequently seen in daily clinical practice. FE is characterized by diffuse rash and fever. FE is classified in 4 types, depending on the primary skin lesion: macular, maculopapular, vesicular, and bullous exanthema. It is of infectious and non-infectious cause. Among the infectious causes the most frequent is the viral one. FE may affect all ages, but especially children and young people. Usually, FE raises important issues of differential diagnosis, because its clinical and etiological complexity. To decide the most appropriate therapeutic and prophylactic measures for FE, it is important to know the clinical criteria and the specific diagnostic methods.

Managing Dermatologic Toxicities of Epidermal Growth Factor Receptor Inhibitors

There is considerable evidence that epidermal growth factor receptor (EGFR) plays an important role in non-small-cell lung cancer tumor growth and proliferation. Clinical experience with EGFR inhibitors, such as erlotinib, gefitinib, and cetuximab, has suggested that there are subgroups of patients with non-small-cell lung cancer that demonstrate dramatic responses to these agents. Researchers have sought to determine whether molecular or clinical characteristics correlate with therapeutic outcomes. Rash, the most commonly reported adverse effect of anti-EGFR therapy, has also been examined as a potential marker of response. Several trials evaluating anti-EGFR therapies have reported a positive correlation between rash and response and even rash and survival. If rash is truly a predictor of outcome, it becomes imperative that clinicians identify effective methods for managing this toxicity to avoid unwanted dose reduction, therapy interruption, delay, or discontinuation in patients experiencing a therapeutic benefit. Unfortunately, because of a lack of well-defined rash etiology, variability of use, and interpretation of rash grading scales, as well as a lack of clinical trials evaluating approaches to rash management, we are left without systematic, evidence-based guidelines for treatment. Preliminary results of a prospective study evaluating a rash treatment algorithm developed at the University of Texas M. D. Anderson Cancer Center have been positive, and there is universal agreement that initiation of more prospective trials to evaluate EGFR-inhibitor rash management is needed.

Can rash associated with HER1/EGFR inhibition be used as a marker of treatment outcome?

Rash is a class effect of HER1/epidermal growth factor receptor (EGFR)-targeted agents, and has occurred with high frequency and in a dose-dependent manner in clinical trials of these agents in cancer patients. Analysis of phase II trials of erlotinib (Tarceva) in non-small-cell lung cancer, head and neck cancer, and ovarian cancer shows a significant association between rash severity and objective tumor response. Rash severity was highly significantly associated with survival in patients with non-small-cell lung cancer receiving erlotinib; median survival in patients with no rash was 46.5 days, compared with 257 days in those with grade 1 rash (P < .0001) and 597 days in those with grade 2/3 rash (P < .0001). Similarly, for the combined non-small-cell lung cancer, head and neck cancer, and ovarian cancer studies, median survival in patients with no rash was 103 days, compared with 191 days in those with grade 1 rash (P = .0001) and 266 days in those with grade 2/3/4 rash (P = .0001). Similar findings have been made with cetuximab (Erbitux) and in some settings with gefitinib (Iressa). The strong association of rash severity with response/survival suggests that rash may serve as a marker of response to erlotinib treatment and may be used to guide treatment to obtain optimal response. Dosing erlotinib at the maximum tolerated dose, which is associated with more frequent and more severe rash, may improve response rates and survival durations. Further study of the potentially important association between rash and outcome of treatment with EGFR-targeted agents is needed.

Evaluating the febrile patient with a rash

The differential diagnosis for febrile patients with a rash is extensive. Diseases that present with fever and rash are usually classified according to the morphology of the primary lesion. Rashes can be categorized as maculopapular (centrally and peripherally distributed), petechial, diffusely erythematous with desquamation, vesiculobullous-pustular and nodular. Potential causes include viruses, bacteria, spirochetes, rickettsiae, medications and rheumatologic diseases. A thorough history and a careful physical examination are essential to making a correct diagnosis. Although laboratory studies can be useful in confirming the diagnosis, test results often are not available immediately. Because the severity of these illnesses can vary from minor (roseola) to life-threatening (meningococcemia), the family physician must make prompt management decisions regarding empiric therapy. Hospitalization, isolation and antimicrobial therapy often must be considered when a patient presents with fever and a rash.

Update on selected viral exanthems

Viral exanthems are common in childhood and account for a large number of patient visits to pediatric or family medicine clinics. Most exanthems are virtually harmless to the healthy child, but others can be signs of more significant systemic disease. Some exanthems that are benign or self-limited in the healthy child may propose significant risk to pregnant or immunocompromised individuals. Therefore, recognition of exanthems, which may be associated with certain viral illnesses, is important for the primary care provider. For example, prompt recognition of a viral exanthem caused by parvovirus may allow a pregnant female from exposing her fetus to a potentially fatal infection, or, if the exposure has already occurred, may indicate the need for appropriate fetal monitoring. In this manuscript, we review the recent literature pertaining to four characteristic exanthems that are thought to be viral in nature: papular purpuric gloves and socks syndrome; pityriasis rosea; unilateral lateral thoracic exanthem; and Gianotti-Crosti syndrome.

Newly recognized infectious exanthems

An exanthem is defined as any rash which is associated with an infectious agent. During the past 6 years, molecular techniques have produced a revolution in clinical dermatology including the exanthems. The infectious agents responsible for many exanthems of previously unknown causes have been uncovered. Included in this review is an update of the rapidly changing spectrum of exanthems, and 10 examples of new viral etiologies of exanthems and two new bacterial exanthems that were recognized during the past 5 years.