Allergic or Irritative Contact Dermatitis: Everything You Need to Know

What Are the Symptoms of Contact Dermatitis ?

Symptoms in the Acute Phase

In the acute phase, contact dermatitis is characterized by skin redness and dry patches that cause intense itching (pruritus). On these patches, vesicles filled with clear fluid burst and ooze, especially after scratching. These lesions appear in the direct contact area with the allergen but can sometimes spread. Sensitive areas such as the eyelids, face, or genital organs may also exhibit edema (swelling).

Symptoms of the Subacute and Chronic Phases

The subacute phase is marked by crust formation, scaling, and skin hyperpigmentation. The chronic phase is marked by lichenification: the skin thickens and becomes rough. These symptoms often affect the hands, which are the main location for contact dermatitis.

Differentiating Between Allergic and Irritative Contact Dermatitis

Examining the lesions is not enough to distinguish allergy from irritation, but their symptoms can differ:
- Allergy generally manifests with significant itching. The symptoms of irritative contact dermatitis are mainly sensations of burning, tingling, and pain.
- In case of irritation, symptoms appear quickly. In allergic contact dermatitis, lesions develop 1 to 3 days after exposure to the allergen, in case of repeated exposure. 
- Allergic contact dermatitis heals slower than the irritative form.

How to Distinguish Contact Dermatitis from Atopic Dermatitis ?

Distinguishing contact dermatitis from atopic dermatitis can be tricky, as their symptoms overlap. Certain features help differentiate them.

Triggering Factors and Location of Lesions

Contact dermatitis is usually caused by exposure to a specific substance and is limited to the contact area (hands, face, neck). It primarily affects adults.
Atopic dermatitis is a chronic disease that alternates between flare-ups and remissions. It typically affects infants and is often associated with other atopic diseases like asthma and allergic rhinitis. The lesions are generally located on the folds (elbows, knees), cheeks, and neck.

Diagnostic Tests

Allergy tests can identify the allergens of contact dermatitis.
The diagnosis of atopic dermatitis is usually clinical (family history of atopy and associated atopic diseases). Sometimes, allergological tests like specific IgE blood levels are necessary.

Preventing Contact Dermatitis

Avoid Skin Contact with Allergens and Irritants

Recognizing specific allergens and irritants is fundamental. Preventing contact dermatitis requires skincare changes, such as using hypoallergenic products.

Tips for Skin Protection

Protecting the skin is a fundamental step in preventing contact dermatitis:

- Limit skin contact with moisture.

- After contact with allergens or irritants, wash hands with lukewarm water and soap-free cleansers, rinse, and dry thoroughly.

- Regularly use emollients for good skin hydration and to strengthen the skin barrier.

- Choose hypoallergenic and fragrance-free products.

- If avoidance is impossible, use protective gloves.