We have the world renowned and experienced dermatologist, Dr. N L Sharma to tell us more about cause, symptoms, precautions and treatment of Dermatitis. Dr. N L Sharma has taught hundreds of dermatologist and has contributed to many lectures, articles, and conferences across the globe.He currently practices at National Skin Clinic, 5 Yamini Shopping complex, Ghuggar, Palampur

Dermatocare: What is Dermatitis? What is Contact Dermatitis?

Dr. N L Sharma: Dermatitis is inflammation of the skin. It has many types like contact dermatitis, seborrheic dermatitis, atopic dermatitis and nummular dermatitis.

Contact dermatitis results from reactions to external contactants. Primarily, it is of two types: allergic and irritant contact dermatitis. Allergic contact dermatitis is a T-cell driven process when small molecule substances (<500 daltons) called haptens when combine with skin proteins and initiate an allergic reaction. On the other hand the irritant dermatitis is an inflammation of the skin resulting from direct toxic effects of the contact substances. It is not an allergic process.

Generally speaking, it can produce red-colored rash primarily on the site of contact and rarely over distant areas as well. The presentation may be in several other forms like erythema multiforme where there will be target type lesions over hands and feet or purpuric lesions (like bleeding spots) over the areas of contact as may happen with some rubber shoe wear, or some pigmentation may appear over contact zones.

Dermatocare: People commonly think Dermatitis is caused by eating certain kind of food, is it true?

Dr N L Sharma: No it is not due to eating certain kind of foods. Instead, it is because of contact with those substances, excepting a rare situation called “systemic contact dermatitis” where a person has got very severe contact allergy to a particular substance like in case of Nickel contact allergy and when the person ingests these substances or nickel-containing foods, he may develop a generalized contact dermatitis.

Dermatocare: What are the common causes behind getting Contact Dermatitis?

Dr. N L Sharma: Most common contactants that cause contact dermatitis are:

• Paraphenylene diamine in hair dyes
• Neomycin in antiseptic creams
• Fragrances in personal care products
• Others like benzocaine, potassium dichromate, carbamates or mercaptobenzothiazole.  

These chemicals are mostly present in various household things or things of common use in our environment like rubbers, sunscreens, nickel polish, anesthetic creams (numbing creams) shoe materials, adhesives and resins and so on.

In other words, the causes may be cosmetics, jewelry, hair dyes, sunscreens, medications of local applications like creams, ointments or eye drops, textiles or other wearing apparels, rubbers, plastics, leather, some industrial and occupational chemicals, or plant antigens.

Dermatocare: What precautions should be taken by the patients of contact dermatitis?

Dr N L Sharma: Once the patient is proved that his problem is contact allergy by the test known as patch test then following precautions or instructions are required:

• Patient must avoid direct skin contact with the allergen, as at present there is no known method to desensitize the patient of these allergens.
• Once the allergen is avoided, improvement occurs slowly within 3-6 weeks or sometimes even longer.
• It may be emphasized that the parts of the skin that come in greatest contact with the substance will have the greatest amount of rash.
• If avoidance does not improve the condition completely then some other cause or another additional contactant must be thought of.
• The contactant avoidance instructions depend upon the allergy the person is having.

Dermatocare: How contact dermatitis is treated?

Dr. NL Sharma: For the purpose of treatment, contact dermatitis may be broadly divided into acute contact dermatitis and chronic contact dermatitis.

In the case of acute contact dermatitis e.g. weeping or oozing dermatitis due to hair dye allergy you need to use systemic steroids for periods varying from 2-3 weeks along with topical therapy. Your dermatologist will also give you instructions as to what all things are to be avoided in the long term.

On the other hand, in the case of chronic dermatitis, systemic steroids should invariably be avoided as the dermatitis is long lasting. In additions to avoidance of the allergen, some local steroids have to be used depending upon the site of the body and the type of lesion. Sometimes even intralesional steroids may have to be injected. In addition, anti-histaminics need to be prescribed. Rarely, systemic immune-suppressants like azathioprine may be required.

Dermatitis especially the contact dermatitis stands a chance for cure provided the causative factor is removed from the environment. We hope that instead of finding fault in food, you would look around for common allergens like artificial jewelry, wristwatch, hair dye, plants like congress grass, skin care products, Dettol, occupational exposure to chemicals, etc.