It is a skin condition accompanied by itching, redness and swelling. In severe cases blisters may also appear on the skin due to long exposure of the allergen with the skin. There are many substances those when come in contact with the skin causes an allergic reaction.
Signs and Symptoms
Signs and symptoms of contact dermatitis are usually found at the site of contact. The area of contact with the allergen becomes red, swollen itchy, sometimes with blisters. Mostly symptoms of contact dermatitis are confined to the area of contact. In rare cases rash can spread to other parts also. Symptoms appear after contact with the allergen for several days.
Common Substances Causing Contact Dermatitis
There are many substances from day to day life that are causes of contact dermatitis. Common allergens responsible for contact dermatitis include:
1) Substances containing metals like nickel and chrome, e.g. jewelry, watch strap, cement
2) Topical applications on the skin e.g. cream, deodorants, perfumes and other cosmetics.
3) Medications especially antibiotics which are applied on the external surface of the skin causes an allergic reaction in some individuals.
4) Certain soaps, detergents, solvents, cause irritation of the skin in many individuals.
5) Insecticide spray or other fertilizer sprays can cause contact dermatitis in many cases.
Diagnosis of Contact Dermatitis
As signs and symptoms appear after few days of the exposure to the allergen therefore, it is difficult to identify the allergen in some cases.
Diagnosis is made by taking complete medical history including use of recent cosmetics, any medications or exposure to an allergen.
Skin patch test is the standard method for the diagnosis of contact dermatitis. In this test the suspected allergen is applied to a small skin area usually on the inner aspect of the upper arm for several days. If signs and symptoms appear on the treated area, contact allergy is diagnosed with the same allergen.
Skin lesion biopsy or culture of the skin lesion may be used to identify other causes for contact dermatitis.
Treatment
- In some cases after the identification of the possible allergen avoidance is the usual treatment for contact dermatitis. Avoidance helps in further exposure to the allergen thus preventing any symptoms to occur.
- Acute signs and symptoms can be treated by the application of topical steroids. Topical steroids can help in relieving the acute signs and symptoms.
- In severe cases oral steroids may be needed if topical applications fail to give relief.
- If infection is present antibiotics are advised.
- Lesions can be washed by daily soaks of potassium permanganate (1:10,000) and Icthammol 10% in glycerin.
Reference:
· Adkinson NF Jr. Drug Allergy. In Adkinson NF Jr., Yunginger JW, Busse WW, Bochner BS, Holgate ST, eds. Middleton's Allergy: Principles and Practice. 6th ed. Philadelphia, Pa; Mosby Elsevier; 2003: chap 92.
· Grammer LC. Drug Allergy. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 275.