Contact allergens

• Small synthetic or natural low-molecular, organic or inorganic substances, which are able to achieve sensitization ( contact allergy) by topical application. The special property of contact allergens is their ability to activate not only the adaptive (acquired) immune system (T-cell reaction) but also the innate immune system (see below immunity). To date, over 4000 contact allergens have been identified.

The detection of a contact allergen is based on anamnesis, clinic and epicutaneous test. Various factors play a role in sensitization:

• Exposure: behavioural habits, amount per area, duration of contact, intensity of contact, localisation (e.g. intertriginous), climate (low air temperature and humidity) influence the sensitising potency.
• Chemical, pharmacological and toxicological properties
• Penetration into the skin (dependence on molecule size, charge, skin health, composition of the product
• Individual, genetic sensitivity (e.g. TNFA-308 G/A polymorphism; Il-16-295 C-C polymorphism; NAT2rapid acetylator phenotype)
• Immune reaction of the body
• Concomitant diseases such as CVI with congestive dermatitis; ulcus cruris and others
• Drugs (increased potential when taking ACE inhibitors, opioids - decreased potential when taking mycophenolate mofetil, MTX; 5- Fluorouracil and others)
• Age: high age reduces the risk of allergic contact reactions

See MOAHLFA Index below.

• Most contact allergens are haptens (haptens + soluble or cell-bound proteins = action as antigen).

• Hit list of contact allergens related to 12,574 epicutaneously tested patients (cited in J. Geier et al. 2011)

The most common allergens (see table) are:

1. Metals like dichromate, nickel (see below nickel allergy 13.3%)
2. Fragrance mix (8.4%)
3. Peru balsam ((7.2%)
4. Fragrance mix II (5.5%)
5. cobalt chloride (3.9%)
6. Colophony (3.7%)
7. Kathon CG (3.2%)
8. turpentine (3.2%)
9. Wool wax alcohols (2.6%)
10. MDBGN (2.5%)
11. Thiuram mix (2.2%)
12. propolis (2.1%)
13. HICC(e.g. Lyral (2.1%)
14. Epoxy resins (1.5%)
15. Composite mix (1.4%)

S.a. Standard allergens for adults and children (see epicutaneous test below)

According to the DKG guidelines, the following test series should be used in standardised blocks. They can be obtained from the services of Almirall . S.a. Epicutaneous test Test series

• DKG standard series
• DKG standard series for children
• DKG External ingredients
• DKG Preservative, e.g. in external
• DKG Topical antibiotics
• DKG Antimycotics
• DKG Corticosteroids
• DKG Local anaesthetics
• DKG Ophthalmics
• DKG Other medicinal substances
• DKG Breakdown of the fragrance mix
• DKG Breakdown of the fragrance mix II
• DKG Other fragrances subject to declaration
• DKG Other fragrances and essential oils (Fragrances)
• DKG retesting for reaction to Peru Balsam
• DKG Disinfectants
• DKG rubber series
• DKG synthetic resins / adhesives
• DKG leather and shoes
• DKG leather and textile dyes
• DKG Plant Ingredients
• DKG Aromatic p-amino compounds
• DKG Construction Main Trade
• DKG hairdressing supplies
• DKG cooling lubricants
• DKG Industrial Biocides

1. Frog PJ et al (1987) Contact allergies to rubber, surgical and vinyl gloves. dermatologist 38: 210-217
2. Frog P et al (1987) Contact allergy to Kathon CG. dermatologist 38: 422-425
3. Geier J et al (2011) Current contact allergens. dermatologist 62: 751-756
4. Hillen U et al (2007) Patch test results in patients with scalp dermatitis: analysis of data from the Information Network of Departments of Dermatology. Contact Dermatitis 56: 87-93
5. Iyer VJ et al (2002) Role of different valence states of chromium in the elicitation of allergic contact dermatitis. Contact Dermatitis 47: 357-360
6. Lindemeyer H et al (1985) Lower leg eczema and contact allergy. dermatologist 36: 227-231
7. Martin SF (2011) Immunology of contact allergy. Dermatologist 62: 739-743.
8. Senff H et al (1991) Contact allergies to newer preservatives. Dermatologist 42: 215-219
9. Uter W et al (1999) The MOAHLFA index in 17 centers of the Information Network of Departments of Dermatology (IVDK) over 6 years. Contact Dermatitis 41: 343-344
10. Wildemore JK et al (2003) Evaluation of the histologic characteristics of patch test confirmed allergic contact dermatitis. J Am Acad Dermatol 49: 243-248