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Posts for tag: Skin

July 26, 2018
Category: Rashes
Tags: Skin   rashes  
Exanthemata with you?
 
 
Among the most common conditions we encounter in pediatrics are rashes. They can have a number of causes including drugs and toxins (as in poison ivy), but today I want to discuss the rashes caused by certain infections.
 
Classically childhood rashes caused by infectious agents were numbered. The numbering was first provided in 1905 and is as follows:
 
  1. First disease is rubeola, aka measles. Measles is caused by measles virus which is highly contagious. It develops 10-20 days after exposure and lasts 7-10 days. Initially the infected person will develop high fever (up to 104 degrees), cough, runny nose, and inflamed eyes. White spots called Koplik’s spots appear in the mouth about 3 days into the infection. A diffuse rash appears on the face and spreads throughout the body three to five days after the start of symptoms. In about a third of patients complications such as blindness, encephalitis, and pneumonia will develop. Also, a recent study revealed that measles infection can make the patient susceptible to other diseases by erasing the immunologic memory your body has developed over time. Thankfully vaccination has made the disease rare.
  2. Second disease is scarlet fever. Scarlet fever is an infection caused by group A streptococcus. This can be strep throat or impetigo. The cause is an erythrogenic toxin which leads to a rough, sandpaper like rash which typically begins in the groin and folds of the arms and legs. Complications of scarlet fever include rheumatic heart disease and glomerulonephritis. Antibiotic therapy, usually penicillin, will treat the infection and protect against rheumatic heart disease. After the rash resolves the skin may peel in a manner similar to a sunburn.
  3. Third disease is rubella which is caused by rubella virus. It is also known as German measles or three day measles. It is a mild infection in which the rash appears about two weeks after infection and lasts for three days. There may be sore throat and fever present as well as joint swelling. The most significant problem resulting from rubella is congenital rubella syndrome. This occurs when a non-immune mother contracts rubella while she is pregnant. This can lead to miscarriage, cataracts, deafness, and congenital heart disease. Thankfully this disease is rare due to vaccination with the MMR vaccine.
  4. Fourth disease is Dukes’ disease. It is an entity that there is some question as to it’s etiology. The prevailing opinion at this time is that it is staphylococcal scalded skin syndrome. This is a rash that appears similar to a sunburn that will occasionally have blisters. It is treated with pain relievers and antibiotics.
  5. Fifth disease is called erythema infectiosum. It is caused by human parvovirus B19. In most people this is a mild infection which first manifests in bright redness to the cheeks hence one of its common names, the “slapped cheek disease”. As time passes the redness of the cheeks fades and a lacy rash appears on the upper and lower extremities. The patient is actually contagious during the asymptomatic period. Once the rash appears it is no longer contagious. In adults and teenagers swelling of joints may occur. The most significant complication with fifth disease is in those who have sickle-cell anemia. These people undergo what is called aplastic crisis. This is characterized by a profound anemia. A pregnant mother who is not immune may also have complications such as congestive heart failure in her baby,
  6. Sixth disease is called roseola infantum. It is cause by human herpesvirus 6 and human herpesvirus 7, and if affects children mainly 6 months to 2 years. It presents with fever, up to 104. The fever lasts a few days, and shortly after the fever breaks, a non-itching rash develops on the trunk and spreads outward. This lasts 1-2 days and then vanishes.
Thank goodness the conditions which we mainly deal with are numbers 2, 5, and 6, but these are only the numbered exanthemata. There are many illnesses which cause rashes.  In fact, just about any viral infection can cause a rash.  However, if your child has an unexplained rash, one that wont go away, or worsens, they should be checked to be safe.
May 04, 2018
Category: Bug Bites
Tags: Bug Bites   Skin  

April Showers Bring May Flowers...And Mosquito Bites

 

April is here, and the weather thus far has been delightfully mild. We all know “April showers bring May flowers.” Unfortunately, those showers leave small puddles of water in our ditches, buckets left in the sand box, and in the oddest places like hollowed spaces in trees. These seemingly harmless collections of water are a breeding ground for the most deadly organism on earth, the mosquito.

Yes, you read that correctly. The mosquito is the deadliest organism on earth because it is the vector for a number of diseases such as malaria, Eastern Equine Encephalitis, St. Louis encephalitis, Japanese encephalitis, yellow fever, dengue, West Nile virus, Zika virus, and my personal favorite, chikungunya. Thankfully, in the US of A most of these diseases are rare due to excellent mosquito control measures by public health agencies. However, these things are still annoying little critters which can ruin your barbecue or birthday party.

Ædes ægypti, Ædes albopictus, Anopheles quadrimaculatus, and Culex quinquefasciatus are the scientific names of four common mosquitoes which plague our area.  (Don’t the names just sound annoying? And sinister?) They all need stagnant water to breed and go through a complicated life cycle which is not relevant to this discussion. What is relevant is that in order for many mosquitoes to be able to produce eggs, they need to have components found in blood. This can be from any animal: reptiles, fish, cats, dogs, birds, horses, and humans. This is where we come into the picture.

What exactly attracts mosquitoes to people in order to siphon off a small amount of blood from them? There are a number of factors which contribute to this: type O blood, heavy breathers, those with a lot of skin bacteria, people with a lot of body heat, children, and the pregnant. A person’s attractiveness to mosquitoes also has a heritable, genetically-controlled component.  That’s all interesting, but how does a mosquito locate someone?

Female mosquitos hunt their hosts by sight and by detecting compounds such as carbon dioxide, octenol, and nonaldehyde.  The last compound is found in perfumes. They also are able to detect chemicals in perspiration. They prefer some people to others because frankly, some people’s sweat smells better to them than others. So when we say your child smells sweeter to the mosquito, we are really only half joking. 

Mosquitos are crepuscular critters.  In other words, they hunt for hosts in twilight (dusk and dawn). During the heat of the day they prefer to hang out in cool areas and only bite if they are disturbed. Otherwise they wait until evening to resume their hunt.

The female mosquito basically has a hypodermic needle for a nose. This is called her proboscis. When she bites someone, she injects her proboscis into the skin and releases a little saliva which is an anticoagulant and sucks out a small amount of blood. (She spits in your skin. Yuck.) It is this saliva which is the means of spreading disease. It’s also the cause of the itching. The saliva causes histamine to be released which produces a red, itchy bump called a wheal to form. This histamine is meant to destroy the proteins left by the saliva. Most of the time this wheal forms immediately, but occasionally it may take hours to a few days to show up.

Once a mosquito bites you there are options to deal with the itching. Antihistamines orally such as Benadryl, Claritin, Zyrtec, Allegra, and Xyzal will help with the itching. Topical Benadryl is also effective. Topical steroid treatments like 1% hydrocortisone cream and triamcinolone cream are another option. Before using any of these it would be best to consult with one of our physicians as to which is best for your child. Even with no treatment, the itching resolves within a few hours. (This was an actual experiment I performed in a medical entomology class in college. We weren’t allowed to scratch the itch.  Worst 2 hours of my life!)

As with so much in healthcare, an ounce of prevention is worth a pound of cure. Here are some ways to prevent the mosquito from ruining your outdoor activities. First, remove sources of stagnant water. Empty old buckets, tire swings, and any other source of standing water that you see. Second, wear clothing which covers as much exposed skin as possible. While this helps, it may not prevent all bites. Third, insect repellents. The most effective are those which contain DEET, but DEET in high concentrations can cause problems in children, so get a product such as Off Family or Off Skintastic. These have a much lower concentration of DEET, generally less that 10%. Parents should apply the repellent. Children should never apply insect repellents themselves. Oil of lemon eucalyptus is quite effective. And finally, citronella is also an effective repellent, although it lasts for a shorter time than others. Fourth, if you are camping be sure to use mosquito netting to keep those pests out of your tent.

Finally, mosquito borne disease in our area is not very common due to excellent mosquito control measures. What we mostly deal with are complications from scratching, like impetigo. If the wheal becomes very red or covered with a crust that looks like dried honey, we should examine your child in the office. However unlikely, if your child has mosquito bites and suddenly develops fever, body aches, headache, and stiff neck, it is imperative that we see them right away. 

So hopefully now you are bettered armed to fight these annoying pests.  Enjoy the mild weather with fun outdoor activities. Just take the precautions which have been discussed and you will keep the mosquitoes at bay.

Fun fact: In Iberville Parish, Louisiana there is a town called Maringouin. This is the Cajun French word for a large swamp mosquito.