The term morbilliform refers to a rash that looks like measles.[1][2] The rash consists of macularlesions that are red and usually 2–10 mm in diameter but may be confluent in places.[3] A morbilliform rash is a rose-red flat (macular) or slightly elevated (maculopapular) eruption, showing circular or elliptical lesions varying in diameter from 1 to 3 mm, with healthy-looking skin intervening.[citation needed]
One cause of morbilliform rash is an allergic reaction to transfused blood/blood components. In such a case, the skin lesions would develop within a few hours (Approx. 4hours) of transfusion along with pruritus. The condition may even present with other symptoms, such as conjunctival oedema, oedema in the lips and tongue, and even localised angioedema. On rare occasions, the condition may even escalate to anaphylactic shock where pulmonary restrictions are seen. The associated cause for this is a reaction against an allergen that is seldom identified during testing. Transfusing products with anti-IgA antibodies to IgA-deficient patients has also been a suspected cause for such reactions. Management usually relates to the stoppage of transfusion for around 30minutes, until given antihistamines take effect. Transfusion may even be continued after, if no further progression is seen.
