Dermatology MCQ - Inflammatory Dermatoses - Eczema of the Eyelids

A 28-year-old woman presents with a 3-week history of pruritic, scaly, and erythematous patches affecting both of her upper eyelids. She reports no visual changes or ocular pain. She recently started using a new eye cream and mascara. Physical examination is significant for mild edema and fine scaling of the eyelid skin, with no involvement of the conjunctivae or perioral area. Which of the following is the most likely diagnosis?

A. Seborrheic Dermatitis
B. Atopic Dermatitis
C. Allergic Contact Dermatitis
D. Irritant Contact Dermatitis
E. Psoriasis

Correct Answer: C. Allergic Contact Dermatitis

Explanation:

• The presentation is highly suggestive of allergic contact dermatitis (ACD). The eyelids are one of the most sensitive sites for ACD due to their thin skin and propensity to react to allergens transferred by the hands or applied directly. The key clues are the timing following the use of new cosmetics (eye cream, mascara), the bilateral involvement, and the morphology of pruritic, scaly, erythematous patches. Common allergens in this context include fragrances, preservatives, and resins in nail polish (transferred by touching the eyes).

• Why the other options are incorrect:

  • A. Seborrheic Dermatitis: While it can affect the eyelids (often as blepharitis), it is typically associated with greasy, yellowish scale and involves other seborrheic areas like the scalp, nasolabial folds, and eyebrows. The history of a new product is a stronger pointer towards ACD.

  • B. Atopic Dermatitis: Eyelid involvement is very common in atopic dermatitis. However, patients with atopic dermatitis would typically have a long-standing history of eczema in other classic flexural areas (antecubital/popliteal fossae) and other atopic features (asthma, hay fever). The acute onset linked to a new product makes ACD more likely.

  • D. Irritant Contact Dermatitis: This is caused by a direct toxic effect of a substance (e.g., soaps, solvents). While possible, it is often associated with a burning or stinging sensation rather than intense pruritus. Allergic contact dermatitis is a more common cause of this specific presentation.

  • E. Psoriasis: Eyelid psoriasis is rare. It would present as a well-demarcated, thick, silvery-scaly plaque, which is not described here. Psoriasis is also less likely to be acutely triggered by a new cosmetic product.

Key Points for Exams

• Pathophysiology: ACD is a type IV (delayed) hypersensitivity reaction. The reaction typically occurs 24-72 hours after exposure to the allergen.

• Common Allergens: For eyelids, think of nail polish (tosylamide/formaldehyde resin), fragrances, preservatives (e.g., Kathon CG, parabens), metals (nickel from eyelash curlers), and components of rubber or glues (in false eyelashes).

• Airborne Contact Dermatitis: Eyelids can also be affected by airborne allergens like plant resins (e.g., sesquiterpene lactones in Compositae plants), epoxy resins, or sawdust.

• Prognosis: Excellent upon identification and avoidance of the causative allergen. Symptoms and signs resolve within days to weeks after the allergen is removed.

• Management:

  1. Strict Avoidance: This is the definitive treatment. The patient should discontinue all suspected products.

  2. Patch Testing: This is the gold standard for identifying the specific allergen and is crucial for preventing recurrence, especially in chronic or recurrent cases.

  3. Topical Therapy: Low-potency topical corticosteroids (e.g., hydrocortisone 1% ointment) are first-line. Potent steroids should be avoided on the thin eyelid skin due to the risk of atrophy, glaucoma, and cataracts. Topical calcineurin inhibitors (e.g., pimecrolimus, tacrolimus) are excellent steroid-sparing alternatives for this sensitive area.

  4. Symptomatic Relief: Cool compresses and oral antihistamines can help reduce pruritus and inflammation.