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Month: January 2021

Penicillin Allergy

Penicillin allergy is reported in roughly 7-10% of the general population and in up to 20% of hospitalized patients. Even though the reported numbers are fairly high, approximately 90% of these reported cases do not actually have a penicillin allergy. Individuals think they are allergic, but in most cases, the symptoms that they experience are either a non-allergic side effect or completely unrelated to penicillin. An allergy to penicillin, however, appears to be the most common medication allergy, along with other antibiotics.

Penicillin is comparatively inexpensive while being very efficacious. This make it both a common as well as a good choice for clinicians to use when an antibiotic is necessary. For those who have a true allergy to penicillin, the penicillin is seen as a foreign “invader” and one’s immune system mounts a defensive response in order to try to subdue the “invader.” When the immune system mounts a response, chemical mediators are released into the bloodstream in order to attack the intruder. As a result of these chemical mediators (e.g., histamine, leukotrienes), the individual may experience itching, hives, and/or swelling. In severe cases, an anaphylactic reaction may occur where individuals may develop wheezing, shortness of breath, rapid heartbeat, and/or drop in blood pressure.

Most people with a probable history of penicillin allergy are given alternative antibiotics in order to treat infections.  In most cases, the replacement antibiotic will be more expensive than penicillin. It also may not be as effective as penicillin. In addition, the use of a replacement antibiotic can result in bacteria developing resistance to these alternative antibiotics, which will be a detriment to the community as a whole.  In the field of allergy and immunology, is important to distinguish between a “false” allergy and a “true” allergy to penicillin and related antibiotics, so that the correct and appropriate antibiotic can be utilized. The evaluation of penicillin allergy requires the use of a standardized penicillin testing protocol. At Black & Kletz Allergy, our board certified allergists routinely perform this procedure in our office. Skin testing has been used for the diagnosis and management of penicillin allergy since the 1960’s.  The procedure is commonly performed with minimal risk.  Penicillin skin testing can be done safely in properly selected patients with suspected penicillin allergy.

The procedure for penicillin skin testing involves 3 steps:

  • Skin prick testing with a small amount of diluted penicillin allergens, negative control solution, and positive control solution.
  • If the prick tests are negative after 20 minutes, intradermal skin testing is performed where a very small quantity of the allergen, negative control solution, and positive control solution is injected into the superficial layers of the skin.
  • If the intradermal skin test in in this second stage is also negative after 20 minutes, the patient will be given 250 mg. of amoxicillin by mouth (i.e., oral challenge) and will be closely monitored for 90 minutes.

If the patient tolerates all 3 stages without any untoward effects, the patient may receive penicillin if needed without an increased risk of an immediate allergic reaction than that of the general population. Penicillin testing should only be performed in a healthcare setting only by an allergist with the knowledge, training, and experience to select appropriate patients for this procedure, interpret the test results, and manage a systemic allergic reaction if it were to occur. This procedure can accurately identify the roughly 9 of 10 patients, who despite reporting a history of penicillin allergy, can receive penicillin safely. It should be noted that most individuals who say that they are allergic to penicillin because “they were told they had a reaction as a young child” turn out not to have a penicillin allergy when tested by a board certified allergist. It is however important to be tested and to not just assume you will be negative. All presumed “penicillin-allergic” individuals should continue to avoid penicillin until they are tested by an allergist.

The board certified allergists at Black & Kletz Allergy have been diagnosing and managing penicillin allergy, as well as other medication allergies for more than 50 years. We treat both pediatric and adult patients. Black & Kletz Allergy has offices in Washington, DC, McLean, VA (Tysons Corner, VA), and Manassas, VA. All 3 of our offices have on-site parking. For further convenience, our Washington, DC and McLean, VA offices are Metro accessible. Our McLean office location offers a complementary shuttle that runs between our office and the Spring Hill metro station on the silver line. For an appointment, please call our office or alternatively, yo

hand with pen drawing the chemical formula of Penecillin

u can click Request an Appointment and we will respond within 24 hours by the next business day. If you have a penicillin allergy or think you have a penicillin allergy, we are here to help you by testing you to see if you are allergic to penicillin. Black & Kletz Allergy is dedicated to providing the highest quality allergy care in a relaxed, caring, and professional environment.

Reactions to Food Additives

The food we consume everyday contains many natural and artificial additives. Most of these additives to food are chemicals and biological substances. In most of the cases, they are usually either preservatives or coloring substances.

Though additives have been used for hundreds of years, there has been an increase in the number and variety of substances added to food in the past few decades. The Food and Drug Administration (FDA) lists more than 4,000 different additives on their Food Additive and Color Additive lists.

Some of us can be “intolerant” to food additives, however, food additives may cause both immediate (i.e., symptoms beginning within a few minutes of eating food) and/or delayed (i.e., symptoms beginning several hours after eating food) hypersensitivity reactions. Immediate reactions are mediated by an antibody called IgE and delayed reactions are usually caused by T-lymphocytes (i.e., T-cells). The exact mechanism of reactivity however, may be unknown in a number of reactions caused by the additives.

Two common additives found in food in the U.S. that need special mention include sulfites and food dyes.


Sulfites are one of the most commonly used preservatives for foods. They reduce spoilage and prevent fruit and vegetable browning. They also have some beneficial anti-oxidant properties. Sulfites are present in dried fruits in high quantities. They are also usually added to baked goods, shrimp, and condiments. Sulfites are also present in several varieties of wines and beers.

There are many case reports of sulfites causing hives (i.e., urticaria), angioedema (i.e., soft tissue swellings), and flare-ups of asthma. The FDA now requires that most preservatives, including sulfites, be cleared mentioned in the food labels. Sulfites can appear as alternate verbiage on product labels and can be written as potassium bisulfite, potassium metabisulfite, sodium bisulfite, sodium metabisulfite, or sodium sulfite.

Sulfite, sulfa, sulfate, and sulfur are 4 terms that sound very similar but are very different when it comes down to their allergy profile. Sulfa drugs contain the sulfonamide molecule and are typically broken down to sulfonamide antimicrobials (i.e., antibiotics) and sulfonamide non-microbials. The chemical structures are different between the sulfonamide antimicrobials and the sulfonamide non-microbials and thus individuals who have allergic reactions to one group should not have allergic reactions to the other group of sulfonamides. It should be noted that approximately 3% of individuals are allergic or have adverse effects from sulfonamide antimicrobials. The sulfonamide antibiotics may include sulfamethoxazole (i.e., Bactrim, Septra), sulfafurazole, sulfisoxazole (i.e., Pediazole), and sulfadiazine. The non-microbial sulfonamides may include Celebrex (i.e., celecoxib), Lasix (i.e., furosemide), Microzide (i.e., hydrochlorothiazide), Imitrex (i.e., sumatriptan), Amaryl (i.e., glimepiride), and Diabeta (i.e., Glyburide).

Sulfates are present in many medications (i.e., magnesium sulfate, ferrous sulfate), supplements (i.e., glucosamine sulfate), and personal care products (toothpaste, shaving foam, shampoo). Sulfates are different chemically from sulfites and sulfa drugs and are unlikely to cause allergic reactions.

Sulfur is a chemical element and omnipresent. It is thus practically impossible to have an allergy to sulfur.

Food Dyes:

Carmine is a coloring agent present in red-colored foods. It is extracted from the insect known as the cochineal. It is known as “cochineal extract” or “natural red 4.” It has been shown to cause facial swelling, rashes, wheezing, and/or anaphylaxis.

Saffron, annatto, and yellow dye # 5 are added to foods to color them yellow. Saffron is a spice that has been around for thousands of years. It can be toxic in larger quantities. An allergy to saffron is known to cause itching, skin irritation, rashes, redness of the skin, and hives. Annato comes from the seeds of the achiote tree and can be found in some cereals, drinks, cheeses, and snack foods. It has been shown to cause rashes and anaphylaxis is some individuals. Yellow dye # 5 (i.e., tartrazine) is known to cause hives and angioedema is selected individuals. It is also known to trigger asthma in some individuals.

It is important to note that any food dye may cause allergic reactions in susceptible individuals. Although food dye allergies are not too common, it is important to be aware that reactions such as itchy skin, redness of the skin, hives, angioedema, and anaphylaxis may occur.


If one experiences untoward reactions to many different unrelated foods or if reactions occur only after eating commercially packaged foods, sensitivity to the additives should be suspected. Maintaining a food and symptom diary can be helpful in narrowing down the additive in question by establishing a temporal relationship between exposure and the onset of adverse effects.

Skin prick testing or blood testing are not useful in the diagnosis of food additive sensitivity; however, they may be useful in ruling out specific foods. Oral food challenges are usually helpful in the diagnosis. In this procedure, foods are eaten in small increments at regular intervals, beginning with a tiny quantity, while closely monitoring for adverse reactions under controlled circumstances with standardized protocols to treat an allergic reaction.


Avoidance of the foods containing the suspected or confirmed sensitizing additive is essential in order to prevent untoward reactions. Careful reading of labels before eating is essential in reducing the likelihood of reactions. Enquiring about the specific ingredients of a dish in restaurants will go a long way in preventing untoward symptoms.

Patients with a history of anaphylaxis triggered by either known or unknown substances should always carry a self-injectable epinephrine device (e.g., EpiPen, Auvi-Q, Adrenaclick) at all times. If the device is used, the patient must go immediately to the closest emergency room.

The board certified allergy doctors at Black & Kletz Allergy have 3 locations in the Washington, Northern Virginia, and Maryland metropolitan area. We have offices in Washington, DC, McLean, VA (Tysons Corner, VA), and Manassas, VA. Our 3 office locations have on-site parking and the Washington, DC and McLean, VA offices are Metro accessible. Our McLean office has a free shuttle that runs between our office and the Spring Hill metro station on the silver line. The allergy doctors at Black & Kletz Allergy diagnose and treat both adult and pediatric patients. To schedule an appointment, please call our office directly or alternatively, you can click Request an Appointment and we will respond within 24 hours by the next business day. The allergy doctors at Black & Kletz Allergy have been serving patients with food additive allergies, food allergies, hay fever (i.e., allergic rhinitis), asthma, sinus disease, hives, eczema, insect sting allergies, medication allergies, and immunological disorders for more than 50 years. If you are bothered from allergies, it is our mission to improve your quality of life by reducing or preventing your unwanted and bothersome allergy symptoms.