Urticaria

I'll keep this short and sweet:  If you want to distinguish between urticaria and urticarial vasculitis, either ask the patient if the lesions last more than 24 hours, or have them come in after having drawn a border around the urticarial lesion, much the same as if you were documenting cellulitic change.  As one of our playas noted, you can also look for petichiae or bruise-like change to sniff out UV, but the easiest way is simply to ask the patient how long they last.

Rocky Mountain Spotted Fever

Rocky Mountain Spotted Fever is a rickettsial disease caused by Rickettsia rickettsii, and the natural history of RMSF goes like this:  1-2 weeks after being bitten by a tick from the Ixodid ticks, primary among them are the wood ticks (Dermacentor andersoni) and dog tick (D. variabilis), the victim develops constitutional symptoms (fever, chills, malaise) and a centripetal rash that begins on the distal extremities and marches inward toward the trunk.  This time lapse from the onset of the rash to the truncal manifestations can be as short as 6 hours.  Over the next couple of days, the rash becomes petichial and hemorrhagic, and if the patient isn't treated by day 5, the fatality rate rapidly climbs.  Problem is, in up to 20% of cases, there is no rash.  The usual cause of death is acute renal failure. If treated in time with a tetracycline derivative or chloramphenicol, the death rate is nil. 

About four years ago, I  had the pleasure of having a different rickettsial disease, R. conorii being the causative organism (bonus: which disease did I have and where did I get it?) and I thought someone was jackhammering the inside of my skull for about a week, in spite of starting Doxy as soon as I figured it out.  Not fun.  

Lupus pernio (Sarcoidosis)

First off, this is a testmanship question.  I just discussed unknown rashes, etc. on African American patients being sarcoidosis until proven otherwise, and then I throw out an image of strange papules on the nose, and- imagine that!- he's African American.  You could win lots o' dough in Vegas if you were to hit the tables with these kinds of odds in your favor.  

Lupus pernio is characteristically violaceous to skin colored, smooth shiny papules and plaques around the nose, cheeks and lips.  It is associated in nearly 75% of cases with chronic fibrotic respiratory tract involvement, so the correct diagnosis is important to the patients because the correct treatment can interrupt a cycle of disease that may cripple or rarely kill the patient.  Lupus pernio is associated with other manifestations of sarcoidosis, including bony involvement, but the primary risk is the association of the pulmonary tree.  

For those of you who got it right, reward yourself by clicking this link:  http://www.youtube.com/watch?v=9bZkp7q19f0

If you missed it, click this link:  http://www.youtube.com/watch?v=pWS8Mg-JWSg

Sarcoidosis

This is a pattern-recognition question.  If you take away the patterned aspect of this Q, you end up with a laundry list of ddxes: everything from infectious (deep fungal, AFB, bacterial, parasitic, viral) to neoplastic (weird CTCLs, etc.) to factitial (excoriated bug bites, etc) to inflammatory.  This is, of course, a special kind of inflammatory condition, and one that is all too common in African Americans.

From now on, for the rest of your natural lives, please remember this:  Any weird rash on African Americans can be sarcoidosis, and the importance of this point is this:  In many cases the skin manifestations of sarcoidosis precedes the other symptoms, and as such is the bellwether for the disease.  The worse the skin disease, the worse the systemic sarcoidosis.  And since we are often tempted to treat inflammatory skin diseases empirically, we can miss an important cutaneous manifestation of a systemic disease.  Given that sarcoidosis can irreversibly damage kidneys, eyes, lungs and liver, it is well worth recognizing the possibility and diagnosing it before the cat, so to speak, gets out of the bag.

Sarcoidosis, like syphilis, is a great imitator.  It can look like many different diseases (see the first paragraph above) and can cause great harm, like lues, if left unrecognized. 

Sarcoidosis is more common in the African American community at large (three times as common as the general population) and is more severe than in Caucasians.  So, in the future, if I throw up an image, and it is from an African American, and you can't tell exactly what it is, your answer should be "sarcoidosis until proven otherwise".

Allergic Contact Dermatitis to Gear Shift Knob (Australia)

This was, no doubt, a challenging question.  The problem with trying to piece together a story for a guy with a localized contact derm on the hand is that you need some history to pull everything together.  If you practice is like ours, most of the time the patient does not present to your office with a known allergen in mind, because if they did, they wouldn't be bothering you with a mystery they've already solved.

In this case, I wanted you to put it all together.  Your clues were what you see above, which is a clear case of localized allergic contact dermatitis.  Second, I gave you some clues:  1) He was a skin cancer patient  2) It was a localized dermatitis secondary to rubber.  At this point (as one of you did) you should be thinking "why did he say skin cancer patient?" and put together that it had to be in a latitude conducive to skin cancer.  But wait!  There's more!  Why the localization to the left hand?  Gotta be an answer.  That was when our Sherlock figured out that in some countries that were formerly part of the British Empire (or influenced by them as in the Japanese) they drive with the shifter on the left, not on the right.  The British Isles are not known for their skin cancer problems, so it had to be either Australia,  or New Zealand.  Playing the odds, since Australia is much bigger than New Zealand, the answer was Australia.  

Australia has a very highly developed derm community, and first among the superstars of Aussie derm is Robin Marks. For a bonus point, what does "Slip, Slap, Slop" mean? Dr. Marks has developed a body of literature which has informed the rest of us on such subjects as which side of the body has more AKs and what is the likelihood an individual AK will turn malignant.  Not bad for a country founded as a penal colony...

Behcet's Disease

Behcet's is a pretty interesting syndrome, in that it affects widely separated parts of the body, and tends to be pretty serious.  Also known as Oculo-Oral-Genital Syndrome, it consists of recurrent aphthous oral ulcers at least three times in twelve months, in conjunction withany two of the following:  retial vasculitis or uveitis, cutaneous lesions such as erythema nodosum, pseudofolliculitis or papulopustular lesions (think lesions similar to fire ant bites), a positive result of a pathergy test or recurrent genital ulceration.  A positive pathergy test is the stimulation of the formation of similar lesions by scratching or puncturing the skin.

The proper way to pronounce Behcet's is Beh-Chets, NOT Beh-shet's.  I would have allowed Beh-Jet's, since the ch sound in Turkish is similar to a j, but nobody answered that way.  

Tuberous Tendinous Xanthomas

Well, this is a repeat question (from May 16th) and so I will direct you to that discussion, but the most important aspect of this question is that many of you got it right.  Please think in terms of depositions into the skin, and then run your differential dx based upon location, appearance and peripheral clues.  You all nailed the elevated lipids, so nice job overall.  By the way, this was repeated in error, and I apologize for not making it a harder Q.  

Necrobiosis Lipoidica

Necrobiosis Lipoidica is a degenerative disorder of collagen, which manifests itself with plaques that are typically erythematous to yellowish in the center, fading to erythematous to violaceous at the periphery.  The usual age on onset is in the thirties, it usually (but not always) accompanies glucose metabolism dysfunction, and it is more commonly than not on women.  The most common laboratory abnormality is an abnormal HgbA1C, but often they also exhibit an elevated fasting blood glucose. 

The lesions can ulcerate as a result of trauma, and can be precipitated by trauma.  The clues to diagnosis are location (pretibial), color (that characteristic yellowish color in the center of the lesion gives it away) and the pertinent negatives: it is not ulcerated, it is not focal like an infection and it is not elevated, as in pretibial myxedema.  It is not annular, like GA, either. And, unlike Erythema Nodosum, it is multicolored and shiny in the center, as opposed to EN which is more focal, usually uniformly red and, if anything, slightly raised. This is a bit atrophic.

As mentioned above, it is more common in diabetics, and used to be known as Necrobiosis Lipoidica Diabeticorum, but  now, since it is not just associated with diabetes, it is simply known as Necrobiosis Lipoidica.

Granuloma Faciale

Granuloma Faciale is a benign inflammatory process which results in elevated papules, nodules and plaques, nearly always on the face but occasionally on other sun-damaged skin.  The lesions can be skin-colored, brown, or erythematous to violaceous, are smooth with a "peau d'orange" appearance.  

Pathology (obtained with a punch biopsy) shows a characteristic Grenz (pronounce "grents") Zone which translates to a clear area between the inflammatory infiltrate and the skin.  It is almost as if the infiltrate were epidermophobic.  One can also see a Grenz Zone in Leukemia Cutis, Cutaneous B-Cell Lymphoma and Lepromatous Leprosy.  

Sous Vide Cooking

Sous vide (pronounced "sooveed") literally means "under pressure", but in reality refers to cooking foods to their optimum temperature to allow the optimum flavor to develop, texture to be displayed and for nutrition to be maximized with any given dish.  First developed in the 1970s by the food scientists who work for the French National Railroad (SNCF), it languished in long-forgotten cookbooks until the late eighties, when a culinary genius named Ferran Adria began using sous vide cooking in his fantastical preparations at his restaurant outside Barcelona named El Bulli, for his two favorite pit bulls.  

Other chefs quickly followed, most notably Thomas Keller from the French Laundry and Per Se, Heston Blumenthal from The Fat Duck, and Grant Achatz, more recently, from Alinea in Chicago.  It is now considered to be a standard form of cooking in nearly all of the best restaurants in the world, for the reasons listed above.  

The former Chief Technology Officer at Microsoft, Nathan Myrhvold, growing bored with his corporate life, bailed out and went to work for Heston Blumenthal, who currently holds the crown as the best restaurateur on the planet, believe it or not as a prep boy, then sous chef.  Anyway, he gleaned enough information from that experience and collaborating with others, including Adria and Keller, to write a fifty pound, five volume  cookbook called Modernist Cuisine.*  

Well, at the same time all this intellectual ferment was taking place, I was in a funk from a cooking standpoint, because many of the great meals I had recently had were not reproducible in my home.  Daniel Boulud, Keller, Charlie Palmer and others were, from a technique standpoint, killing me.  So, when Myrhvold came out with MC, I jumped on it, reading it cover to cover figuring out what I had been missing. Mostly, as it turns out, it was techniques that were dependent upon equipment I didn't have, and chief among those techniques was sous vide cooking.

After researching my choices, I bought a Sous Vide Supreme water oven, and became an instant convert.  The first four meals I cooked were the best chicken, duck, shrimp and fish I had ever eaten in my life, and it was at home, not in a 5 star restaurant!  Now, my wife Cindy and I cook 90% of our main courses using sous vide techniques.**

Here's what you all really want to know:  The reason sous vide cooking works so well is that at roughly 154 degrees Fahrenheit, collagen starts to foreshorten, which causes the tissue you are cooking to contract, which then expels both flavorful ingredients as well as liquids- the juices you try so hard to preserve in your meals. If you cook the meat instead at 140 or even lower, for a longer period of time, you will find the flavors remain intact, the juices remain in the meat and you end up with a far superior culinary result.  

Equally amazing is that if one cooks, say, a tough cut of meat such as a brisket or short ribs, for a long period of time (48 to 72 hours) the collagen becomes gelatinized which adds both to the flavor and the texture of the food.  

In the last half decade or so, we have been able to be our own publisher and PR agent (via Facebook), we can distribute original video productions (YouTube) and now, we can literally reproduce world class cuisine at home, with a modicum of new equipment.  Now, that's cool!

*Myrhvold now has a more accessible version of MC called Modernist Cuisine at Home.  It is markedly less expensive, more accessible and the recipes use equipment that is more reasonable than the high priced gadgets featured in MC.  

**I now have three different options for cooking sous vide, and at times use all three of them to prepare multicourse meals.