Rosin Allergy

messy make-up image by PHOTOFLY from

So, you have an allergy to colophony, what does that mean exactly? Your immune system reacts to each exposure of colophony or rosin to your skin with its defence mechanisms. Biologist do not know specifically why some people develop allergies, and sometimes it takes many years and multiple exposures before an allergy appears. If you have eczema, rosin sensitivity might be the cause.

What is Rosin?

Rosin, sometimes called colophony or Greek pitch, is a solid form of resin obtained from pines and other conifers. In commerce, it is referred to as crude turpentine. Rosin is made by heating fresh resin to vaporise the liquid terpene components. It is semi-transparent and its colours range from yellow to black. At room temperature, rosin is brittle, but it melts when subjected to hob heat levels.

Uses of Rosin

Rosin is used in adhesives, paints, inks, textiles, soap and even paper products. The texture and other physical properties make it popular in varnishes, especially those for musical instruments. It can be used for sealing wax and in various industrial adhesives. Finally, it is best known for its use on bows for string instruments.

Rosin in Products

If you have a rosin allergy, check all your household products, since it is used in everything from cosmetics to chewing gum. Rosin might show up in your make-up bag in mascara, lipsticks, eye shadows, concealer creams or nail polish; or your bathroom in wart remover, haemorrhoid cream, hair removing wax, transparent soaps, dental floss or sunscreen. Any semi-industrial products like sticking plasters, tapes, glues, fireworks, grease remover or fly strips can contain rosin as well. Finally, pay attention to your firewood, because burning conifers turn their resin into rosin and fling it into the air.

Allergic Reactions

One common reaction is dermatitis, more commonly known as hives or a rash on the skin, and the other is asthma or restricted air flow. Although the reaction occasionally shows up within 24 hours of contact, most reactions don't show up for one to three days after exposure. It happens like this: first, the skin becomes red, inflamed and itchy, and then it might blister and get even itchier. According to Rosin-Factory, "If exposure is continued, the dermatitis may eventually become chronic with thickened, lichenified or leathery skin.


To check yourself for rosin allergy, you test a small area of skin using the repeat open application test, called ROAT. Be careful which allergies you test this way, since some chemicals can be severely irritating, and always talk to your dermatologist first. For the next seven days, apply the rosin twice a day to a small patch of skin such as the inside of the elbow. If after seven consecutive days you do not have a reaction, you probably are not allergic. However, remain alert for symptoms in the future, since you might still develop an allergy with continued exposure.

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