Allergy Notes, Evidence-based Information by Board-certified Physicians

When it comes to skin health, many factors can contribute to rashes, hives, and other dermatological issues. One often-overlooked factor? Vitamin B12 levels . While this essential nutrient is crucial for energy production, nerve function, and red blood cell formation, both deficiency and excess of vitamin B12 have been linked to a variety of skin conditions, including chronic urticaria (hives), pruritus (itchiness), and other allergic reactions. When Too Much of a Good Thing Backfires A patient had recurrent urticaria—red, itchy welts that seemed to have no clear cause. Alongside her skin symptoms, she had been experiencing fatigue for months, prompting her to start taking large doses of vitamin B12 supplements in hopes of boosting her energy levels. However, as part of her laboratory workup, her primary care doctor discovered something surprising: her vitamin B12 level was 1,900 picomoles per liter, far above the upper range of normal (typically 200–900 pmol/L). After discontinuing th...

68% of caregivers incorrectly treat children's asthma exacerbation with albuterol, most undertreat

Increased asthma morbidity and mortality is associated with inappropriate home self-management skills. This study included caregivers of 84 children with asthma aged 4 to 14 years, presenting to the emergency department (ED) with an asthma exacerbation. National Asthma Education and Prevention Program guidelines were used to classify home albuterol use as appropriate or inappropriate. Home albuterol use for the current asthma exacerbation was categorized as: - inappropriate in 68% of participants - appropriate in 32% Incorrect home albuterol use included: - undertreating, including not giving albuterol frequently enough, and without albuterol at home. - no spacer - overtreating - overreacting - using a controller medicine for quick relief Those with appropriate albuterol use were more likely to have their child hospitalized for asthma in the past 48 months. A significant proportion of caregivers (68%) incorrectly treat children's asthma exacerbation with albutero...

Which antihistamines to use in chronic kidney disease and hemodialysis?

The general agreement is that some first generation antihistamines are safe, e.g. diphenhydramine, hydroxizine, chlorpheniramine. Some studies in the recent years confirmed that the second generation antihistamines are also safe but the dose may need modification. Oral Antihistamines (click to enlarge the image ). Evidence from the multiple-dose study supports the clinical use of cetirizine for ESRF patients on HD. Thus, it is concluded that a prescription of 5 mg cetirizine three times a week during the predialysis period will be the effective and safety renal dosage for ESRD patients on HD. No significant relationship was observed between the terminal elimination half-life of loratadine or descarboethoxyloratadine and creatinine clearance. Hemodialysis augmented endogenous clearance by less than 1%. The disposition of loratadine is not significantly altered in patients with severe renal insufficiency nor is hemodialysis an effective means of removing loratadine or descarboethoxylora...

What are the normal serum immunoglobulin levels (IgG, IgA, IgM)?

Serum levels of IgM, IgG and IgA vary with age, gender and race. The IgG and IgA concentrations in children show a gradual rise with increasing age. The IgA level is generally about the same in both sexes. Girls typically have higher IgM and IgG levels than boys. The confidence interval bounded by two standard deviations about the mean excludes 5% of apparently healthy controls. Elevated IgM, low IgA, low IgG, low IgM, and elevated IgA are the commonest changes observed in apparently healthy humans. Humoral immunodeficiency is commonly defined as IgG, IgM or IgA level that is two standard deviations (2 SD) below the mean level for IgG, IgM or IgA, respectively, for the particular age group and gender. Serum levels of IgM, IgG and IgA. Source: Pediatrics, 1966 and Immunologic disorders in infants and children , by E. Richard Stiehm, Hans D. Ochs, Jerry A. Winkelstein. Typical pattern of immunoglobulin levels (IgG, IgA, IgM) in humoral immunodeficiency. Click here to enlarge the table . ...

Tezepelumab vs. Dupilumab in Severe Asthma: Head-to-Head Real-World Data Shows No Clear Winner

In the evolving landscape of biologic therapies for severe asthma, two heavy hitters stand out: dupilumab (targeting IL-4/IL-13 downstream in the type 2 inflammatory pathway) and tezepelumab (blocking TSLP upstream, with potential broader effects across T2-high and T2-low phenotypes). While both are FDA-approved for severe asthma, direct comparative real-world evidence has been scarce -until now. The study authors conclude that, in this real-world cohort, dupilumab and tezepelumab appear comparably effective at preventing exacerbations and reducing steroid reliance - no evidence that tezepelumab's upstream mechanism translated to superior outcomes overall. For clinicians managing severe asthma, this suggests that - pending more data - either biologic is a reasonable option, guided by patient-specific factors like T2 biomarker profile, comorbidities, insurance/cost, administration preferences, and side-effect considerations rather than expecting a dramatic efficacy edge from one ove...

The "Safer" Hair Dye Ingredient That's Now the 2025 Contact Allergen of the Year: Toluene-2,5-diamine sulfate (PTDS)

A chemical often marketed as a gentler alternative in PPD-free hair dyes has a new spotlight: toluene-2,5-diamine sulfate (PTDS) has been named the Allergen of the Year for 2025 by the American Contact Dermatitis Society (ACDS). PTDS , also called toluene diamine sulfate or 2,5-diaminotoluene sulfate, is an aromatic amine commonly used in: - permanent and semi-permanent hair dyes - bleach-toners - other coloring products It's frequently found in "PPD-free" formulations as a substitute for paraphenylenediamine (PPD), the classic culprit behind many hair dye allergies. While it helps some people with PPD allergy avoid reactions, PTDS itself is a potent contact allergen—often underdiagnosed because it's not routinely included in standard patch test series! Patch test positivity rates show its relevance: around 1.4–1.7% in North American and European data, with one Australian study reporting up to 12.9%. Hairdressers and frequent home hair dyers face the highest risk of...

The term "asthma" is a Greek translation of gasping or panting

It is widely accepted that the medical terminology has its roots in ancient Greek and Latin. Greek words have been used not only in the field of medicine but also in every day language for many centuries. The actual term asthma is a Greek word that is derived from the verb aazein , meaning to exhale with open mouth, to pant. The expression asthma appeared for the first time in the Iliad by Homer, with the meaning of a short-drawn breath, but the earliest text where the word is found as a medical term is the Corpus Hippocraticum. However it is difficult to determine whether in referring to "asthma," Hippocrates and his school (460-360 B.C.) meant an autonomous clinical entity or simply a symptom. The best clinical description of asthma in later antiquity is offered by the master clinician, Aretaeus of Cappadocia (1st century A.D.). The numerous mentions of "asthma" in the extensive writings of Galen (130-200 A.D.) appear to be in general agreement with the Hip...

Biologics vs. JAK Inhibitors for Atopic Dermatitis: Which One Wins for Your Patient? A 2026 Practical Guide

Atopic Dermatitis (AD) remains a burdensome chronic inflammatory skin condition affecting quality of life, often accompanied by comorbidities such as asthma, allergic rhinitis, or food allergies. While most patients respond to topicals, 10 -30% require systemic therapy. The review article in JACI goes over targeted options beyond older immunosuppressants (e.g., cyclosporine, methotrexate), focusing on: Biologics (monoclonal antibodies targeting type 2 inflammation) : - Dupilumab (blocks IL-4/IL-13) - widely used, approved from 6 months of age, strong for comorbid asthma or other type 2 diseases, but can cause conjunctivitis. - Tralokinumab and lebrikizumab (IL-13 specific) - similar efficacy, potentially better ocular tolerability. - Nemolizumab (targets IL-31) - stands out for rapid itch (pruritus) relief. The biologics requires subcutaneous injections, have slower onset (4–8 weeks), but also require minimal lab monitoring, and have a generally favorable safety ...

2025: A Breakthrough Year for Chronic Urticaria - New FDA Approvals Reshaped Treatment

Chronic urticaria, encompassing chronic spontaneous urticaria (CSU) and chronic inducible urticaria (CIndU), affects a substantial portion of the population worldwide and imposes a heavy burden due to persistent symptoms like hives, itching, and angioedema, often inadequately controlled by standard treatments. Current first-line therapy relies on nonsedating H1-antihistamines, with omalizumab (an anti-IgE biologic) as the mainstay for refractory cases. However, omalizumab achieves complete resolution in only about 45% of patients and rarely induces lasting remission after discontinuation. Excitingly, the therapeutic landscape for refractory CSU has expanded dramatically in recent years, with several new approvals and promising agents targeting both IgE-dependent and non-IgE pathways. Dupilumab (Dupixent) , an IL-4/IL-13 inhibitor, gained FDA approval in April 2025 for H1-antihistamine-refractory CSU in adults and adolescents ≥12 years, validating the role of type 2 inflammation in CSU...

New Hope for Peanut Allergy: Oral Remibrutinib (Rhapsido) Shows Rapid Protection

A promising new oral treatment could transform how we manage severe food allergies. At the 2026 American Academy of Allergy, Asthma & Immunology (AAAAI) annual meeting in Philadelphia, researchers presented phase II trial results for remibrutinib (Rhapsido), an oral Bruton's tyrosine kinase (BTK) inhibitor developed by Novartis. In the study, adults (ages 18-55) with confirmed peanut allergy received different doses of remibrutinib twice daily for 4 weeks or placebo. The goal was to see if the drug could help them tolerate peanut protein without a reaction. The results were striking and dose-dependent: - 40% of those on the lowest dose (10 mg twice daily) tolerated at least 600 mg of peanut protein - roughly 2.5 peanuts. - 50% succeeded on 25 mg twice daily. - An impressive 87% on the highest dose (100 mg twice daily) reached this threshold. The safety profile looked reassuring, with no major concerns around infections, blood counts, liver enzymes, or other worrisome side effec...

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