A 61-year-old man in Bengaluru, India, went to an emergency room after feeling nauseated and then fainting twice in quick succession, once for about three minutes and again for about two. Doctors first looked for problems in his brain and heart. The clue that mattered turned out to be something he had done two days earlier: he had dyed his hair.
His doctors at Fortis Hospitals concluded that he likely had delayed anaphylactic shock following hair dye exposure, an unusual presentation of a severe, whole-body allergic reaction. Kiran Kuraning and colleagues described the case in the July issue of the Indian Journal of Case Reports.
Because his first symptoms were fainting and low blood pressure rather than hives or wheezing, the report shows how anaphylaxis can hide behind what looks like a different emergency.
Fainting First, Swelling Later
The man had high blood pressure and ischemic heart disease, for which he had previously undergone coronary artery bypass surgery. His family reported no seizure-like movements, loss of bladder control, or post-episode confusion. On arrival, his blood pressure was 80/60 mm Hg, and doctors noted mild swelling around his right eye.
Given the repeated fainting, doctors considered a brain problem, but a brain MRI and an EEG did not explain the episodes. Because of his low blood pressure, he was admitted to intensive care, where tests for infection, tropical fevers, and heart damage came back negative.
Meanwhile, the swelling around his right eye spread to both eyes, and then his entire face, and his blood pressure kept falling despite intravenous fluids.
Only a detailed history revealed that he had applied an artificial hair dye two days before coming to the hospital. He had developed mild itching on his scalp, neck, and face afterward and had treated it himself with the antihistamine cetirizine for two days. He had also spent two to three hours a day walking outdoors, with significant sun exposure, over those two days.
A Reaction That Took Its Time
Using World Allergy Organization criteria, doctors diagnosed anaphylaxis, possibly caused by the hair dye. They treated him with an epinephrine injection into the muscle, intravenous hydrocortisone, antihistamines, and aggressive fluids. Because his blood pressure stayed low, they started an intravenous epinephrine infusion that ran for 16 hours.
Over the next 24 to 36 hours, his blood pressure gradually stabilized, and the facial swelling eased significantly. After 48 hours in intensive care, he moved to a general ward. He was later sent home with a five-day course of oral medications, counseled about the risk of future reactions, and referred to a dermatologist.
The authors suggested that his early itching and later collapse may reflect a combination of early and delayed immune reactions, and they raised the possibility of a delayed or biphasic anaphylactic response. They also noted that ultraviolet exposure may worsen hair dye allergy by chemically modifying allergens such as para-phenylenediamine, or PPD, the main sensitizing ingredient in permanent hair dyes. The report did not identify which ingredient in his dye was responsible, and its title describes the reaction only as likely linked to the dye.
Most Dye Reactions Stay on the Skin
Allergic reactions to hair dye are increasingly common and mainly involve PPD, but systemic reactions such as anaphylaxis are rare and may present atypically, the authors wrote. Most reactions are delayed skin allergies that appear within 24 to 72 hours as itching, redness, and swelling of the scalp, forehead, eyelids, or neck. Britain’s National Health Service likewise says symptoms can take up to 72 hours to appear and that anaphylaxis from hair dye is rare.
Severe swelling from hair dye can also be misread. In a 2002 Danish study in Contact Dermatitis, researchers identified 55 people with severe, acute allergic skin reactions to hair dye whose main symptom was intense swelling of the face, scalp, and ears, which was often mistaken for angioedema. Five were admitted to the hospital.
Immediate, whole-body reactions are rarer still. A 2019 Korean case report of hair dye-induced contact anaphylaxis noted that only a few such cases had been reported worldwide, and it cited a 1997 forensic report of a fatal anaphylactic reaction to hair dye.
The Indian authors also warned about cross-reactivity. People sensitized to PPD may react to related chemicals such as toluene-2,5-diamine, even in products labeled PPD-free.
What a Patch Test Can and Cannot Catch
The FDA advises rubbing a small amount of dye inside the elbow or behind the ear, leaving it for two days, and skipping the dye if a rash appears. It says the test should be done every time, including at salons.
Skin testing is not foolproof for immediate-type allergies, however. In a 2026 Contact Dermatitis report, doctors at Geneva University Hospitals described a patient with severe hair dye anaphylaxis whose skin prick tests to toluene-2,5-diamine and PPD were negative. The diagnosis came instead from laboratory blood cell tests, which were strongly positive for toluene-2,5-diamine.
Anyone who develops swelling of the face, lips, or throat, fainting, dizziness, or trouble breathing after using hair dye should call 911 or seek emergency care, even if days have passed. People who have reacted to a dye before should avoid it and talk with a dermatologist or allergist before coloring their hair again.
Key Questions Answered
What happened to the man?
Two days after dyeing his hair, he fainted twice, developed spreading facial swelling and persistently low blood pressure, and needed intensive care, including a 16-hour epinephrine infusion.
Why was the case unusual?
Hair dye reactions usually stay on the skin, and anaphylaxis is rare. His reaction began with fainting and low blood pressure, and it developed over days.
What ingredient is usually responsible?
Para-phenylenediamine, or PPD, is the main cause of hair dye allergies, though the report did not confirm the culprit in this case.
Does a patch test guarantee safety?
No. The FDA recommends one before every use, but a 2026 case showed that skin tests can miss some severe immediate allergies.
What should someone do if symptoms appear after dyeing?
Seek emergency care for swelling of the face or throat, fainting, or breathing trouble, and avoid the product in the future.
