Case report attributes a man's fainting and refractory shock to a hair dye applied two days earlier

The report's own title hedges. Kuraning and colleagues published it as "Cosmetic catastrophe: A case report of delayed anaphylactic shock likely following hair dye exposure" ^[24]. The doctors did not identify which ingredient triggered the reaction ^[22]. Para-phenylenediamine enters the account through earlier research the authors cite, in which ultraviolet light enhances that compound's allergy-triggering effects; they raise it because the man spent two to three hours outdoors in the sun each day after dyeing his hair ^[21][12].

The diagnosis rested on a sequence: recent dye use, the itching that followed, rapidly worsening facial swelling, and blood pressure that would not come up ^[13]. His doctors read the early scalp itching as a mild reaction that later progressed, and offer a biphasic pattern, seen in about 5% of anaphylaxis patients, as one possible explanation; they say it remains only a possibility ^[20]. That 5% is drawn from anaphylaxis in general.

What the episode cost in time is easier to pin down. The epinephrine drip ran about 16 hours before his pressure held ^[15]. Three days of treatment brought the blood pressure up and the facial swelling down ^[16]. Five further days followed in a general ward before discharge ^[17]. That puts the stay after diagnosis at least eight days as an inpatient, beginning in intensive care ^[25][7].

The conclusion the team drew is procedural: ask about recent use of products such as hair dye when fainting, facial swelling or shock has no other explanation ^[23]. The base rate argues against expecting it. Most allergic reactions to hair dye stay where the dye touched the skin, as itching, redness and swelling, and reactions involving the whole body are uncommon, the man's doctors wrote ^[19].