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Dermatitis- Cause, Symptoms, Precautions And Treatment

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Dermatitis- Cause, Symptoms, Precautions And Treatment

Dermatitis is a broad medical term describing inflammation of the skin. It includes various clinical subtypes such as atopic dermatitis, seborrheic dermatitis, nummular dermatitis, and contact dermatitis. Each form has distinct causes and clinical features. This article focuses specifically on contact dermatitis, addressing its etiology, symptomatology, preventive strategies, and therapeutic options based on the latest scientific evidence.

What is Contact Dermatitis?

Contact dermatitis is an inflammatory skin condition triggered by exposure to exogenous agents. It manifests in two primary forms:

  • Allergic Contact Dermatitis (ACD): A delayed hypersensitivity reaction involving T-cell mediated immunity. Small molecular weight allergens (<500 Daltons), known as haptens, penetrate the epidermal barrier and conjugate with skin proteins, forming complexes that elicit an immune response.

  • Irritant Contact Dermatitis (ICD): This variant arises from the direct cytotoxic effects of substances on the skin, without immune mediation. It is the most common occupational skin disease globally, accounting for approximately 80% of all contact dermatitis cases (Source: American Contact Dermatitis Society, 2024).

Symptoms of Contact Dermatitis

Clinical presentation varies depending on the severity and type of exposure. Common manifestations include:

  • Erythematous rash localized to the contact area

  • Target or annular lesions

  • Purpuric patches (resembles subdermal bleeding)

  • Hyper- or hypopigmentation in chronic cases

Notably, the rash may appear in distant sites due to systemic spread or autoeczematization.

Causes of Contact Dermatitis

Contact dermatitis can be triggered by a variety of substances.

Allergen Name Common Sources to Avoid
Paraphenylene Diamine (PPD) Hair dyes, black henna tattoos, textile dyes
Neomycin Antiseptic creams, topical antibiotic ointments
Fragrances (e.g., cinnamal, hydroxycitronellal) Perfumes, scented soaps, shampoos, deodorants, moisturizers
Nickel Artificial jewelry, watch straps, bra hooks, belt buckles, jean buttons
Formaldehyde & Formaldehyde-Releasers Nail hardeners, hair straighteners, cosmetics, textiles, cleaning agents
Benzocaine Throat lozenges, dental gels, first-aid creams
Potassium Dichromate Cement, leather goods, construction materials
Carbamates & Thiurams Rubber gloves, elastic materials, rubber footwear
Mercaptobenzothiazole (MBT) Rubber gloves, tires, sports shoes
Isothiazolinones (e.g., MI/MCI) Wet wipes, baby products, moisturizers, household cleaners, shampoos
Cocamidopropyl Betaine Shampoos, bubble baths, facial cleansers
Essential Oils (e.g., tea tree, lavender, citrus) Natural or organic skincare, massage oils, aromatherapy products
Disperse Dyes Dark-colored synthetic fabrics, especially nylon, polyester
Formaldehyde Resins Wrinkle-free or permanent-press clothing, especially cotton blends
Sunscreen Agents (e.g., Oxybenzone, Octocrylene) Sunscreens, BB creams, anti-aging creams with SPF
Acrylics & Methacrylates Artificial nails, dental materials, hearing aids, orthopedic appliances
Lanolin Emollient creams, lip balms, nipple creams
Propylene Glycol Lotions, injectables, topical medications, processed foods

Precautions 

For individuals diagnosed with contact dermatitis through a patch test, the following precautions are essential:

  1. Avoid Direct Contact: Patients must avoid direct skin contact with identified allergens, as there is currently no known method to desensitize individuals to these substances.
  2. Monitor Improvement: After eliminating contact with the allergen, skin improvement may take anywhere from 3 to 6 weeks, or sometimes longer.
  3. Localized Reactions: The areas of skin that come into the most contact with the allergen will typically exhibit the most severe rash.
  4. Consider Other Allergens: If avoidance does not lead to complete improvement, it may be necessary to investigate other potential allergens or irritants

Treatment

Treatment varies depending on acute versus chronic manifestation:

Acute Dermatitis

  • For intense weeping or oozing lesions, especially after PPD exposure:

    • Systemic corticosteroids for 2–3 weeks

    • Topical corticosteroids and emollients

    • Long-term counseling on allergen avoidance

Chronic Dermatitis

  • Prolonged corticosteroid use is discouraged.

  • Treatment includes:

    • Topical corticosteroids as per body area and lesion type

    • Intralesional steroids for thickened plaques

    • Antihistamines for pruritus

    • Rarely, systemic immunosuppressants like azathioprine for recalcitrant cases

Conclusion

Contact dermatitis is preventable and manageable, provided the inciting agent is correctly identified and eliminated. Overemphasis on food triggers often delays diagnosis—attention should instead focus on common culprits such as hair dyes, artificial jewelry, skincare products, textiles, and occupational irritants.

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