Mercury in dermatology

Mercury is a highly toxic, silvery-white, shiny metal, which is the only metal that remains liquid at normal temperatures. Whether as elemental mercury, mercury vapor, mercury I and II salts or organic mercury compounds, it remains harmful to health in any form. Mercury can be absorbed through inhalation of mercury vapour and atomization of mercury salts. It is absorbed through the skin and mucous membranes. Elemental mercury is the most vaporizable form of the metal. Even at room temperature, compression or slight movement, mercury gives off vapors.

In dentistry, elemental mercury is used in the manufacture of amalgam fillings. The toxic potential of mercury in dentistry is limited to mercury vapor.

Mercury is well absorbed by inhalation. Oral absorption is low. Mercury can accumulate in the brain and kidneys.

Former indications:

• Syphilis (mercury smear cures/oral and parenteral applications)
• Freckles: A mercury-based freckle ointment (Hg praecipitat alb./Bismut subnitricum aa 2.0 -Ung. leniens, Ung. cerei aa ad 20.0) was already used in Viennese dermatology (v. Hebra). These were massaged into the skin in the evening after washing with soap. Sublimate ointments (hydr. bichloratum 0.5-3% in a lanolin/paraffin mixture) were more effective. At the turn of the 20th century, a 15% borax solution (sodium borate) was recommended as a largely harmless bleaching agent.
• Melasma: Various mercury ointments were also used here.
• Other diseases: Mercury ointments were also used for psoriasis and lichen planus.

In case of poisoning (non-absorbable sublimate):

• Milk and egg white (precipitation of mercury)
• Gastric lavage with activated charcoal

In case of poisoning (absorbed mercury)

• Dimercaprol, dimercaptopropanol sulphonate (DMPS)
• D-penicillinamine

The following significant chronic side effects accompanied mercury therapy for centuries, known were:

• Stomatitis mercuralis
• Enteritis with diarrhea and vomiting
• Colitis mercuralis
• nephrosis
• Polyneuritis mercuralis with radiating sharp pain in the extremities
• Follicularly emphasized mercurial exanthema
• Adynamia (E. Feer 1923), a chronic clinical picture in children that was also referred to as vegetative neurosis (Feer's disease) and was later identified as chronic mercury poisoning
• Amalgam intolerance

Metallic and inorganic mercury:

• Acute intoxication: initial gastrointestinal symptoms, then kidney damage (first polyuria, then oligo- or anuria), followed by mucomembranous colitis with severe colic.
• Chronic intoxication: stomatitis with metallic taste, mercury seam on the gums, central nervous phenomena - erectile dysfunction, intention tremor, concentration disorders, speech disorders.

Organic mercury (highly lipid-soluble/severe neurological damage)

• Acute intoxication: excitation, paresthesia, tremor, cramps
• Chronic intoxication: visual and hearing disorders, paralysis, psychotic states

Inorganic mercury (absorption only with oral intake/water-soluble; renal accumulation and elimination; mainly renal and gastrointestinal symptoms)

• Mercury (I) chloride = calomel
• Mercury (II) chloride= sublimate (corrosive poison)

Organic mercury (good absorption with oral intake, accumulation in gEhrin, main excretion via the intestine. Mainly central sympotmatic):

• Mersalyl (former diuretic)
• Methylmercury cation
• Dimethylmercury (fungicides)

Local and systemic mercury applications (Hydargyrum, Mercury) have a long dermatological history dating back to the early Middle Ages. Arab physicians were the first to use mercury to treat a wide range of diseases. They brought this therapy to Europe (Italy). From 1500 onwards, mercury was a standard herpeutic against syphilis. It was usually administered in ointment form, later also orally and parenterally. The oldest method of treating syphilis was the so-called "smear cure", in which metallic mercury was introduced into the organism in the form of a gray ointment. The German Pharmacopoeia originally prescribed a 33% trituration of metallic Hg in mutton tallow for Ung. cinereum. Later, the following composition was recommended:

• Hydragyrum 100.0
• Adeps sil. 130.0
• Seb. oliv. 700,0

Lassar mixed this "gray ointment" with a little cinnabar, which gave it a reddish hue. The not inconsiderable side effects accompanied mercury therapy for centuries.

Freckles: A mercury-based freckle ointment (Hg praecipitat alb./Bismut subnitricum aa 2.0 -Ung. leniens, Ung. cerei aa ad 20.0) was already used in Viennese dermatology (v. Hebra). These were massaged into the skin in the evening after washing with soap. Sublimate ointments (hydr. bichloratum 0.5-3% in a lanolin/paraffin mixture) were more effective. At the turn of the 20th century, a 15% borax solution(sodium borate) was recommended as a largely harmless bleaching agent.

Melasma: Various mercury ointments were also used here.

Other diseases: Mercury ointments were also used for psoriasis and lichen planus.

Today, mercury applications are generally considered obsolete due to their severe side effects.

1. Bourgeois M et al. (1986) Mercury intoxication after topical application of a metallic mercury ointment. Dermatologica 172:48-51.
2. Karow T (2024) Pharmacology and toxicology. Karow-Pharma, 23rd edition 1320-1321