Carmine is red dye that has been used for centuries in clothes, cosmetics, and other consumer products.
Allergic contact dermatitis (ACD) is an important disease that notably affects 72 million Americans each year.1 The economic impact of this disease is high in terms of both patient morbidity and loss of income, school, and work, not to mention significant expenditures for visits to health care providers and for medicaments. A correct diagnosis of ACD will improve, prevent, or “cure” the dermatitis and decrease overall costs to the health care system.1 Once patch testing is performed and a culprit has been identified, education becomes the critical intervention to ensure adherence to an avoidance regimen. With allergen avoidance, remission of the dermatitis ensues. If patients are unable to comply with the avoidance regimen, they become at risk for recurrent or sustained dermatitis or progression to a systematized presentation.2,3
Figure 1. Raw, crushed cochineal41 yields the red dye.
The 2 main types of contact dermatitis are irritant and allergic, with irritant contact dermatitis (ICD) being the most common. These 2 pathologies are similar in that they develop in response to an external stimulus and are exacerbated by increased contact time and rate of substance release. ICD may occur in anyone who is exposed to an irritating substance with significant duration or in significant concentrations such as chronic or frequent water exposure, abrasive cleansers, detergents, and soaps, and is characterized by a rapid-onset inflammatory process by which the innate immune response is activated to an irritating stimulus.4 ICD can at times precede or be a concomitant diagnosis with ACD.5,6
ACD is a delayed type-IV hypersensitivity reaction that can occur due to a large number of chemicals from poison ivy to fragrances or preservatives in shampoos. Although ACD often presents locally, it may also demonstrate systemic effects secondary to allergen sensitization. The evaluation of ACD fits well with theranostic theory, as the epicutaneous patch test diagnostic evaluation dictates the avoidance management in each individual patient.
Although ACD is not “curable,” many individuals will achieve complete remission with assiduous avoidance. This articles highlights the use of carmine red in various industries and its clinical implications, as well as testing for carmine sensitivity and pearls for treatment.
Carmine is a vibrant scarlet dye that has been used for centuries in clothes, cosmetics, and other consumer products. It is derived from Dactylopius coccus, a scale insect (small insects of the order Hemiptera) that is more commonly known as cochineal. When the cochineal is crushed it reveals the sought after red dye (Figure 1). Not uncommon among the animal kingdom, female cochineals are much larger (4-6 mm) than males (2-3 mm); however, the females are immobile and rely upon their smaller, winged male counterparts for reproduction.7 Cochineals maintain a parasitic relationship with various prickly pear cacti, of which, many of these cacti species were artificially selected and bred for the purpose of creating a sustainable source of cochineal. The dye has a rich and varied history. (See www.the-dermatologist.com/resource/allergen-focus.)8-10
To obtain high quality carmine, only the largest female cochineals must be harvested. This is difficult considering that the mature females are attached to the prickly pear cactus in a randomized assortment among immature female cochineals (Figure 2). While it would be much easier to harvest entire colonies of cochineals, the immature insects dilute the higher quality dye produced by the mature females.7
Figure 2. Cochineal insects on a prickly pear cactus.42
Collected cochineals are killed via boiling, sun drying, or baking. The dye is extracted using either a water or ethanol solution with a subsequent alkaline extraction (ie, sodium hydroxide, potassium hydroxide, or ammonium hydroxide). This solution is then dried to form a reduced liquid or solid, effectively producing cochineal or cochineal extract. At this stage, the extract can be used in consumer products, further purified to create biologic stains, or manipulated into an insoluble aluminum lake using aluminum hydroxide—of which the latter may also be used in consumer products.7 In all, it may take as many as 70,000 to 100,000 insects to make 1 kg of cochineal dye.11 The final product may be highly variable, provided the process of cochineal collection, dye extraction, and extensive filtration of insect products. Carmine dye may contain insect parts that may not have been removed in the filtration and extraction process.
Article continues on page 2