Treatment

Once the patch testing is completed the patient may have

• a clear diagnosis – including the exclusion of allergic contact dermatitis, and appropriate advice and treatment given
• a possible diagnosis – a trial of avoidance of allergen is advised with follow-up to confirm/refute the hypothesis
• an indefinite diagnosis - further patch testing may be required and further information obtained from the patient/workplace, to determine the materials/series that need to be tested (1)

Avoidance of allergen is the cornerstone of the management of the condition (2):

• advice patients about the importance of allergen avoidance at home and in the work place
• protective gear such as gloves or masks can help in minimising future allergen exposure
• provide written information regarding all identified allergens, the names of allergens, its synonyms, common uses, and examples of the types of products that may contain it
• when purchasing skin care products or new products, advice patients to check the ingredient lists for known allergens
  • if patients wish to use a new skin care product, instruct them to perform a repeat open application test - apply a small amount of product to the volar aspect of the forearm twice a day for 1-2 weeks to see for any eczematous reaction (3)

Topical treatments available for the condition include:

• emollients
  • restores skin barrier function and prevents painful cracking of the skin
  • apply frequently during the day, preferably a lighter moisturiser, and a more lipid-rich, fragrance-free, greasy emollient at night
• soap substitute to minimise irritation
• topical corticosteroids
  • apply once or twice a day for affected areas for 4-6 weeks. Reassess the condition.
    • if resolving, reduce frequency
    • if severe, may require twice a week maintenance
  • short term use is recommended since they inhibit repair of the stratum corneum and induce skin atrophy
  • in moderate to severe dermatitis, severity of the condition will determine the strength and the period of use
• topical calcineurin inhibitors
  • use of topical calcineurin inhibitors is off-label
  • applied once or twice daily for 4-6 weeks and review
  • should be considered for use on the face and neck since prolonged steroid use in these areas will cause steroid induced atrophy
• potassium permanganate soaks
  • for acute weeping stages and blistering eruptions
  • dissolve 400 mg tablet (Permitab) in 4 L of water to make 1:10 000 solution
  • affected areas are soaked for 10-15 minutes
  • once or twice daily until lesions dry up (usually 2-5 days)
  • used together with topical steroids and emollients (3)

Sedating antihistamines can be used for night relief of irritable dermatitis (4).

In some instances systemic corticosteroids may need to be considered

• short courses during the acute phase of a severe contact dermatitis may be required (3)

If there is visible secondary infection, take a swab and begin treatment with appropriate oral antibiotics

• flucloxacillin or clarithromycin (if the person is allergic to penicillin) is the recommended first-line treatment (1)

For patients with chronic dermatitis unresponsive to conventional topical therapy, the following may be used as second line treatment options:

• psoralen combined with ultraviolet A light (PUVA)
• narrow band ultraviolet B treatment
• systemic treatment with immunomodulators such as methotrexate, ciclosporin, or azathioprine (2)

Topical tacrolimus has been effective in treating nickel model allergic contact dermatitis. Oral retinoids (alitretinoin) have given good results in chronic hand dermatitis.

References:

1. Johnston GA et al. British Association of Dermatologists' guidelines for the management of contact dermatitis 2017. Br J Dermatol. 2017;176(2):317-329
2. Fonacier L, Bernstein DI, Pacheco K, et al; American Academy of Allergy, Asthma & Immunology; American College of Allergy, Asthma & Immunology; Joint Council of Allergy, Asthma & Immunology. Contact dermatitis: a practice parameter - update 2015. J Allergy Clin Immunol Pract. 2015 May-Jun;3(3 Suppl):S1-39.
3. Rashid RS, Shim TN. Contact dermatitis. BMJ. 2016;353:i3299.
4. Usatine RP, Riojas M. Diagnosis and management of contact dermatitis. Am Fam Physician. 2010;82(3):249-55.