Skin Care Myths: You Cannot Be Allergic to a Product You’ve Used for a Long Time

This is one of my favorites. I see several patients every day with a drug allergy or contact allergy; last week I saw a pleasant gentleman with an intractable itchy rash on his hands, arms, and abdomen. Read more

February 25, 2008 | Filed Under Allergies, Mini Med School: Derm 101, Rashes, Skincare Myths | 1 Comment 

Brachioradial Pruritis: Scratching Makes the Itching Worse

A 45 year old woman presented to my office complaining of a burning itching rash on both her arms. Read more

February 24, 2008 | Filed Under Mini Med School: Derm 101, Rashes | 2 Comments 

Nickel Named Allergen of the Year

nickel-2.JPGForget the Oscars. The American Contact Dermatitis Society has just held its annual red carpet event — allergens of the year. The winner for the 2008 Allergen of the Year is … nickel.

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February 17, 2008 | Filed Under Allergies, Mini Med School: Derm 101, Rashes | 3 Comments 

Psoriasis Website

I seemed to have a run on psoriasis patients this week. It is not surprising; psoriasis is often worse in the winter when the air is dry and when there is less sunlight. Both warm humid air and sunlight will improve psoriasis.

If you have psoriasis, please visit the National Psoriasis Foundation site –it’s an excellent resource about psoriasis and its treatments. They will also help you find a dermatologist in your area who treats psoriasis!

See also: Severe Psoriasis Linked to Increased Risk of Death

Photo of psoriasis from University of Manchester School of Medicine website.

January 26, 2008 | Filed Under Rashes | Leave a Comment 

Itchy Henna Tattoo

henna.JPG

A patient of mine presented last week with an itchy tattoo. He had been on a cruise and had this temporary henna tattoo placed on his right arm. A few days later when everyone else’s tattoos were fading, his got darker and became itchy. The redness and itching became much worse over the next week. What happened?

My patient is allergic to para-phenylenediamine (PPD).

PPD is a coloring that is used in permanent hair dyes. It is also sometimes added to henna to create a dark color, or “black henna,” for temporary tattoos.

Contact dermatitis is a delayed type hypersensitivity reaction; it’s the same type of allergy that occurs after exposure to poison ivy or poison oak. It takes 1-2 days to develop the rash from an allergen, and the response can last weeks.

If you are allergic to hair dye, then you should be weary of getting a henna tattoo. PPD can also been found in printer inks, black rubber, and photodevelopers.

What is more problematic (especially for those studying for the derm boards) is that PPD can cross-react with sundry other things, causing an identical allergic reaction. These include PABA sunscreens, azo dyes (found in fabrics), benzocaine anesthetics, and sulfa drugs.

My patient was treated with topical corticosteroids and the itchy rash resolved. Some patients actually need oral steroids to treat this; consult your physician if you think you are having an allergic reaction to your tattoo.

And don’t get a tattoo that you wouldn’t want your dermatologist (or mother) to see.

January 15, 2008 | Filed Under Mini Med School: Derm 101, Rashes | 1 Comment 

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