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Zika – What You Need To Know

August 22, 2016 4:28 am ,
July 25, 2016
By Maureen S Hamel MD, Brenna L Hughes MD MSc – Modern Medicine Network

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Zika virus was first identified from the Rhesus monkey in 1947 in the Zika Forest, Uganda. The virus was subsequently isolated from humans 5 years later. Since the 1950s 3 major outbreaks have been reported: 2007 in the Yap islands of Micronesia; 2013 in French Polynesia; and most recently in 2014–2015 in Brazil. Because the symptoms of Zika are similar to several other viruses such as chikungunya and dengue fever, it is likely that cases in other regions have occurred but have not been identified.

Prior to 2007, Zika was not reported outside of Africa and Asia, and since it was first reported in Brazil in May 2015, the virus has swiftly spread across South and Central America and into the Caribbean. During this time, Brazil has seen a concomitant increase in the frequency of neonatal microcephaly. These parallel findings suggested a link between Zika and birth defects—a relationship not previously identified. With the outbreak of Zika infection and its probable link to teratogenicity has come vast media attention. Zika was declared a Public Health Emergency of International Concern by the World Health Organization (WHO) in February 2016 and it is predicted that transmission to new countries and territories will continue during the upcoming months to years. In fact, in June 2016, the WHO took the momentous step of recommending that women living in Zika-endemic areas delay child-bearing.

Vector

Zika is transmitted to humans via the Aedes species of mosquitoes. These mosquitoes are also responsible for the transmission of dengue fever and chikungunya viruses. The Aedes mosquitoes are unique; unlike other species of mosquitoes, they are aggressive daytime biters. The primary species transmitting Zika to humans is the Aedes aegypti and the secondary species is the Aedes albopictus. The virus is transmitted during a blood meal. Both Aedes aegypti and Aedes albopictus have been found in the United States, primarily in the southeastern region. Aedes albopictus is the vastly more prevalent species (Figure 1).

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Disease features

Zika is a flavivirus, a single-stranded RNA virus. Zika virus is challenging to identify and therefore challenging to study for several reasons.

  1. First, only 1 in 5 people infected with the virus will become ill.
  2. Not only are disease symptoms usually mild, they can be identical to many other common mosquito-transmitted viruses. Because mild viral illnesses are ubiquitous in many of the regions affected with Zika, people may never realize they have been infected. In patients who do experience symptoms, these symptoms will occur between 3 and 12 days after being bitten by an infected mosquito and will last between 2 and 7 days. Symptoms include mild fever, maculopapular rash, headache, arthralgias, and myalgias. One distinctive feature of Zika is non-purulent conjunctivitis; while this complaint is also found among patients with dengue fever and chikungunya, its presentation seems to be much more common and severe in Zika cases. Zika has not been shown to cause hemorrhagic fever, and disease requiring hospitalization and/or resulting in death is rare. As in the case of other viral illnesses, once infected, individuals are protected from future infection.

Infection prevention

The most effective methods of disease prevention are to protect against mosquito bites and to reduce opportunities for vector proliferation. The Centers for Disease Control (CDC) has recommended long-sleeved shirts and long pants in Zika-infected regions both in the daytime and at dusk. Mosquito bed nets are essential if air conditioning or screens are unavailable. The CDC also recommends the application of Environmental Protection Agency (EPA)-approved repellents to skin and clothing. These products include DEET (N,N-Diethyl-meta-toluamide) and premethrin. DEET-containing products are recommended for skin application and provide the longest-lasting skin protection. Premethrin should be used on clothing and netting. Products approved by the EPA are not expected to cause adverse health effects and are safe in pregnancy. In fact, reports have suggested it may soon be possible in some states to receive Medicare/Medicaid for DEET products. Finally, vector reduction is essential for disease pre vention. The CDC has advised state and local governments to urge residents to reduce standing water by eliminating old tires, old barrels, and other vessels for standing water. An initiative has begun to treat standing water and wetlands with larvicides such as the bacterial insecticide Bti (Bacillus thurengiensis israeliensis).

Transmission

Although Zika was discovered more than 60 years ago, because adverse pregnancy or birth outcomes have never been previously reported, research into perinatal infection and perinatal transmission is limited and ongoing. Two theories of perinatal transmission exist. The first is transplacental transmission. This theory proposes that virus is transferred directly from the mother to the fetus via the placenta. Once infected, the fetus suffers neural damage as a direct result of the virus. The other theory is one of placental inflammation, which proposes that maternal viral infection creates a placental inflammatory response. This response in turn results in fetal neural damage. The former theory is similar to other documented models of viral transmission and poor outcomes and is the more widely accepted view.

Zika can be sexually transmitted from men to their sexual partners and the possibility of male-to-female sexual transmission with subsequent fetal transmission raises concern. The first documented case of sexual transmission occurred in 2008; this was male-to-female with the sexual contact occurring a few days before the onset of symptoms in the man. With regard to the current outbreak, the first report of sexual transmission was in February 2016. However, as of March 2016, 6 cases of sexual transmission of Zika from men to their sexual partners had been confirmed in the United States. All cases of sexual transmission have been from a man to his sexual partner via vaginal, anal, or oral sex and the sexual contact has occurred before, during, or soon after resolution of symptoms consistent with Zika infection. One recent report out of New York City suggests the first case of female-to-male transmission, however it remains under investigation and it is currently unknown whether asymptomatic men can transmit virus to their sexual partners.

The duration of Zika within the male genitourinary tract is unclear and the process of viral shedding within the genitourinary system is not well understood. As such, Zika testing for the sole purpose of assessing the risk of sexual transmission is not recommended. Because of the risks of transmission from men to women and particularly the risk to the fetus during pregnancy, the CDC has set forth guidelines regarding sexual activity (see bellow)

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Two cases of peripartum transmission (ie, transmission at delivery or in the immediate postpartum period) from mother to infant have been reported; both cases resulted in mild disease for the mothers and neonates and no long-term morbidity. While viral particles have been detected in breast milk, breastfeeding has yet to be documented as a mode of transmission. Likewise, infection status after blood transfusion has yet to be reported; however, it is expected, as Zika was found in 2.8% of donors during the 2013 French Polynesian outbreak.

In June 2016, the NEJM published the first report of an affected fetus in the United States. Driggers et al. describe the case of a 33-year-old woman who traveled to Guatemala, Mexico, and Belize during her 11th week of pregnancy. A day after her return to the United States she developed symptoms of a viral infection including rash, mild fever, myalgia, and ocular pain. Her partner had similar symptoms. Serologic testing was positive for both IgM and IgG antibodies against Zika, consistent with Zika infection. Fetal ultrasounds after symptom resolution were negative for intracranial pathology. At 19 weeks, a detailed ultrasound demonstrated brain abnormalities such as bilateral frontal horn enlargement, upward displacement of the third ventricle, absence of the cavum septum pellucidum, and a decrease in head circumference from the 47th to the 24th percentile for gestational age. Fetal MRI confirmed abnormalities of the lateral ventricles, the third ventricle, and the corpus collosum. The patient elected for termination at 21 weeks’ gestation. Postmortem examination of the fetus confirmed the presence of Zika in the amniotic fluid, placenta, fetal brain, muscle, liver, lung, and spleen.

The research regarding perinatal Zika infection, while at times compelling, is limited. And many questions remain. The challenge for patients as well as practitioners is facing the unknown. The true incidence of Zika among pregnant women is unclear, as is the rate of vertical transmission. In turn, among fetuses to whom the virus is transmitted, the rate and range of clinical manifestations cannot be predicted. Indeed it seems there is a delay between maternal exposure, fetal transmission, and ultrasonographically detectable abnormalities, but this time course is not well understood. The case by Driggers et al. demonstrates that fetal abnormalities may not be seen for up to 9 weeks after maternal exposure.

Finally, and perhaps most distressing to expectant mothers, is the unknown prognosis for infants born with Zika infection. Using data from the current outbreak in Bahia as well the previous outbreaks in Micronesia and French Polynesia as models, Johansson and others estimate the risk of microcephaly among infants of mothers infected by Zika to be between 0.9% and 13%. While this estimate is concerning, it must be considered with caution as it is based on modeling and limited retrospective data. Likewise, microcephaly is only one of several potentially adverse outcomes. It is well established that infants with severe microcephaly from other causes will experience a range of neurologic sequelae, but it is unclear if this is true for all cases of Zika-related microcephaly. Neurologic problems can range from intellectual disability to sensory deficits to seizures; they can be mild, severe, or life-threatening. Long-term outcomes are not at all clear and will not be for years to come.

Countries where pregnant women are advised not to travel:

  • American Samoa
  • Argentina
  • Aruba
  • Bahamas
  • Barbados
  • Belize
  • Bolivia
  • Bonaire
  • Brazil
  • Cape Verde
  • Caribbean
  • Chile
  • Colombia
  • Costa Rica
  • Curacao
  • Dominican Republic
  • Ecuador
  • El Salvador
  • French Guiana
  • Guadeloupe
  • Guatemala
  • Haiti
  • Honduras
  • Jamaica
  • Martinique
  • Mexico
  • Nicaragua
  • Panama
  • Paraguay
  • Peru
  • Puerto Rico
  • Samoa
  • Saint Martin
  • Suriname
  • Tonga
  • U.S. Virgin Islands
  • Uruguay
  • Venezuela
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Common pediatric disorders in skin of color

August 16, 2016 5:52 pm ,
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August 10, 2016
By Lisette Hilton / Dermatology Times

While pediatric atopic dermatitis and acne have some similarities among skin of color and lighter-skin children, there are important differences when these common skin conditions affect darker skin types, according to Nanette Silverberg, M.D., clinical professor of dermatology and pediatrics, Icahn School of Medicine at Mount Sinai and chief, pediatric dermatology, Mount Sinai Health System.

Starting with eczema

Atopic dermatitis is the most common skin condition of childhood and affects about 25 percent of children in the U.S., according to Dr. Silverberg, who presented on the topic at The Skin of Color Seminar Series, held earlier this year in New York City.

“In particular, there have been studies that have shown atopic dermatitis is more common in children of African American descent or of Afro-Caribbean descent,” she says. “It certainly represents a very concerning issue in children of color.”

Differences in atopic dermatitis can occur in the presentation and severity among children of color.

“In somebody who is very light skinned, eczema is going to be red. But in children of color, we see much less erythema. We see much more in the way of lichenification, or thickening of the skin, and more follicular prominence. These are particularly vexing types of eczema, in that the lichenification, or lichenoid, type of dermatitis is often very thick and very itchy. And the follicular type can be quite deceptive. You don’t see redness. You don’t necessarily see thick or oozing skin, but it is incredibly itchy and it significantly affects children psychologically,” Dr. Silverberg says.

One of the major issues with treating children of color is that there are differences biologically, in terms of the basis of atopic dermatitis, according to the dermatologist.

In African American children, it has been demonstrated that there are reductions in ceramide content, and that could be the reason the skin barrier is not working as effectively as it should be. In children who are Caucasian of European descent, eczema is more associated with a filaggrin defect, she says.

“Filaggrin defects, particularly in Asian children, are somewhat different than those noted in Caucasian children, so we know there are some reasons biologically that the kids may be a little different,” Dr. Silverberg says.

As a result, dermatologists treating children of color who have eczema often need to use thicker emollients, including emollients that might have extra ceramide content or extra balanced fat content to enhance the skin barrier.

“We’re still moving forward to see whether the biologic basis of eczema affects how children respond to treatment. In atopic dermatitis, many of the kids with atopic dermatitis will manifest in early childhood with a lot of hypopigmentation or lightness of the skin. So, pigmentary alterations, which we see in kids of color, are temporary but are sometimes very noticeable and can concern parents,” Dr. Silverberg says. “But this generally resolves, and that’s something we can reassure parents about.”

Acne

Acne is common and comes with different concerns in children with skin of color.

“Whereas many of our Caucasian patients talk about the actual pimple lesions, most of our African American patients and many of our Hispanic and Asian patients will obsess over post-inflammatory pigmentary alterations after their acne clears,” Dr. Silverberg says. “So, there’s a focus in the skin of color acne patients, even in the teenagers, on specifically pigmentation issues.”

Hispanic pediatric patients tend to have the most severe acne types among children of skin of color, Dr. Silverberg says.

“We don’t see as much in the way of cystic acne in African American patients, historically and in the literature,” she says. “So, the population that we tend to focus on for more severe treatment or treatment, like isotretinoin, are usually Hispanic teenagers. It’s an important consideration because they have some tendency to have the cystic component, although you can see it in everybody, it seems to be the most concerning amongst that population in the teenage years.”

Dermatologists treating these children need to pay special attention to communicating the need for using good sun protection to enhance pigmentation returning properly. It’s also important to work with patients to develop a skincare regimen that’s effective both at clearing current lesions and preventing new lesions, so the pigmentation improves over time, according to Dr. Silverberg.

“There are some wonderful new acne guidelines that have come out recently from the American Academy of Dermatology … saying it’s clear that most patients of color will respond quite nicely to the products we have available, including topical retinoids … as well as azelaic acid, which has been demonstrated to be beneficial in improving both tone and skin lesions,” she says.

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Study shows poor skin cancer survival in patients with skin of color

August 15, 2016 5:45 am ,

Dermatologist urges everyone to be aware of their risk and take steps toward prevention, detection
SCHAUMBURG, Ill. – July 28, 2016

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 Because Caucasians have a higher skin cancer risk than the general population, people with skin of color may believe that they don’t need to be concerned about this disease — but new research reveals this to be a dangerous misconception.

According to a study published online in the Journal of the American Academy of Dermatology on July 28, although melanoma incidence is higher in Caucasians, patients with skin of color are less likely to survive the disease.

“Everyone is at risk for skin cancer, regardless of race,” says board-certified dermatologist Jeremy S. Bordeaux, MD, MPH, FAAD, one of the study authors. “Patients with skin of color may believe they aren’t at risk, but that is not the case — and when they do get skin cancer, it may be especially deadly.”

Researchers at Case Western Reserve University in Cleveland utilized the National Cancer Institute’s Surveillance, Epidemiology and End Results database to study nearly 97,000 patients diagnosed with melanoma, the deadliest form of skin cancer, from 1992 to 2009. Although Caucasian patients had the highest melanoma incidence rate, they also had the best overall survival rate, followed by Hispanic patients and patients in the Asian American/Native American/Pacific Islander group.

African-American patients had the worst overall survival rate, and they were also the group most likely to be diagnosed with melanoma in its later stages, when the disease is more difficult to treat. According to the study, however, the timing of the diagnosis is not the only factor that affects this group’s survival rates, as African-American patients had the worst prognosis for every stage of melanoma.

Dr. Bordeaux says these differences in survival rates may be due to disparities in the timeliness of melanoma detection and treatment among different races; for example, patients with skin of color may not seek medical attention for irregular spots on their skin because they don’t believe these lesions pose a risk. Additionally, he says, there may be biologic differences in melanoma among patients with skin of color, resulting in more aggressive disease in these patients. More research is necessary to determine why survival rates differ among different ethnic groups, he says, but in the meantime, patients of with skin of color should be aware of their skin cancer risk.

“Because skin cancer can affect anyone, everyone should be proactive about skin cancer prevention and detection,” Dr. Bordeaux says. “Don’t let this potentially deadly disease sneak up on you because you don’t think it can happen to you.”

Ultraviolet radiation exposure is the most preventable skin cancer risk factor, Dr. Bordeaux says, so everyone, regardless of skin color, should take steps to protect themselves from the sun’s harmful UV rays. The American Academy of Dermatology recommends seeking shade, wearing protective clothing, and using a broad-spectrum, water-resistant sunscreen with an SPF of 30 or higher.

Although sun protection is important for everyone, Dr. Bordeaux says, people with skin of color are prone to skin cancer in areas that aren’t commonly exposed to the sun, including the palms of the hands and the soles of the feet. He says these individuals should be especially careful to examine hard-to-see areas when monitoring their skin for signs of skin cancer, asking a partner to help if necessary.

“Skin cancer is most treatable when detected early, so everyone should regularly examine their skin for new or suspicious spots,” Dr. Bordeaux says. “If you notice any spots that are different from the others, or anything changing, itching or bleeding on your skin, make an appointment to see a board-certified dermatologist.”

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