Cobalt chloride

Table of contents

• What is cobalt chloride?
• How does cobalt chloride work?
• Which conditions is it used or studied for?
• How is cobalt chloride given?
• What do the clinical trials show?
• What side effects are known?

What is cobalt chloride?

Cobalt chloride is a metal salt of cobalt, a metal found in nature that is used to make steel and appears in ceramics, cement, paints, leather goods, and other metal products.^[2] In the clinical trial described here, cobalt chloride appears as a test substance in a patch test panel for diagnosing allergic contact dermatitis. The registry records list it as "Kobaltchlorid 1%, Testsalbe", a 1% test ointment applied to the skin.^[1] Cobalt was once used to treat different types of anemia, but there is no good scientific research to support its use for any condition.^[2]

How does cobalt chloride work?

In patch testing, a small amount of the suspected allergen is applied to the skin under an occlusive patch. If a person is sensitised to the substance, a local allergic reaction develops at the application site. Cobalt chloride is included in a panel of metal allergens to detect contact allergy to cobalt. The trial measured the concordance (agreement) between two patch testing methods: the investigational hydrogel allergen and the reference petrolatum allergen, using Cohen's kappa calculation and positive and negative percent agreement.^[1]

Which conditions is it used or studied for?

• Allergic contact dermatitis — a skin reaction that occurs when the skin comes into contact with a substance to which a person is allergic. The trial studied cobalt chloride as part of a panel to diagnose this condition.^[1]
• Eczema — a condition causing inflamed, itchy, cracked, and rough skin. One registry entry for the trial also lists eczema among the conditions studied.^[1]

How is cobalt chloride given?

In the clinical trial, cobalt chloride was applied to the skin as a 1% test ointment (Testsalbe) in a volume of 20 microlitres.^[1] The route of administration was cutaneous use, meaning it was placed directly on the skin as part of a patch test procedure. The trial compared two formulations: a hydrogel-based investigational allergen and a petrolatum-based reference allergen.^[1]

What do the clinical trials show?

The registry contains one trial identifier, NCT04500834, listed under the title "Metal Panel Patch Test". The trial appears in two registry entries with different statuses: one entry lists the trial as withdrawn with a planned enrollment of 300 participants, and another lists it as authorised with a planned enrollment of 395 participants.^[1][1] Both entries describe a Phase 3 interventional study evaluating the diagnostic efficacy and safety of investigational allergens, including cobalt chloride, and the overall safety and performance of the investigational panel device.^[1]

The primary outcome measure was the concordance (agreement) between the hydrogel investigational allergen and the petrolatum reference allergen patch testing methods, calculated using Cohen's kappa and by positive and negative percent agreement.^[1] The trial included cobalt chloride among twelve metal allergens tested, alongside nickel, copper, tin, manganese, ammonium, zinc, gold, sodium, vanadium, and potassium dichromate.^[1]

What side effects are known?

According to a supplementary source, taking cobalt chloride by mouth at a dose of 1 mg daily for up to 90 days seems to be safe in a few small studies.^[2] Taking cobalt in higher doses or for longer periods is possibly unsafe and might cause heart problems, hearing loss, or vision loss in some people.^[2] When inhaled, cobalt is possibly unsafe and might cause heart problems, lung disease, hearing loss, and vision loss in people exposed to cobalt dust in certain industries.^[2]