Defining Eczema

Eczema is a general term for a group of inflammatory skin conditions that cause the skin to become dry, itchy, flaky, and bumpy. The terms eczema and dermatitis are often used interchangeably to describe a polymorphic inflammatory reaction pattern involving the epidermis and dermis. Some dermatopathologists suggest using the term ‘spongiotic dermatitis’ to reflect the underlying histopathologic changes.

There are several different types of eczema, including atopic dermatitis, contact dermatitis, dyshidrotic eczema, neurodermatitis, nummular eczema, seborrheic dermatitis, and stasis dermatitis.

Differentiating Atopic Eczema and Seborrheic Eczema

A. Atopic Eczema (Atopic Dermatitis)

Atopic dermatitis is the most common and chronic form of eczema. It often starts in infancy or early childhood but can persist into adulthood or develop later in life.

It is characterised by dry and intensely itchy patches of skin that may crack, ooze, or form crusts. The appearance can be red, gray, brown, or purplish depending on skin tone. Commonly affected areas include the face, hands, inside the elbows, and behind the knees.

B. Seborrheic Eczema (Seborrheic Dermatitis)

Seborrheic dermatitis is a chronic, relapsing form of eczema that usually appears on the scalp but can occur anywhere there are a lot of oil-producing (sebaceous) glands, such as the chest, groin, beard region, and nose.

It causes red, greasy, and inflamed skin covered with white or yellowish scales. Researchers believe that seborrheic dermatitis occurs when a fungus known as Malassezia interacts with oils on the skin, causing an inflammatory reaction.

Pathophysiology of Eczema

A. Immune Dysregulation in Atopic Dermatitis

Atopic dermatitis involves a complex interplay of immune responses. Type 2 immune cytokines, such as IL-4 and IL-13, play important roles in skin barrier dysfunction and allergic inflammation.

B. Skin Barrier Dysfunction in Atopic Dermatitis

Key proteins responsible for epidermal function include filaggrin (FLG), transglutaminases, keratins, and intercellular proteins. Defects in these can facilitate allergen and microbial penetration.

C. Pathophysiology of Seborrheic Dermatitis

Seborrheic dermatitis is often triggered by an inflammatory reaction to excess Malassezia yeast on the skin. The immune system may overreact to this yeast.

Clinical Features, Triggers, and Exacerbating Factors

A. Atopic Eczema

• Intense itching (pruritus)
• Dry, cracked, crusty, scaly, or thickened skin
• Red, white, purple, or grey skin, depending on skin tone
• Blisters or bleeding
• Triggers include: allergens, irritants, temperature changes, infections, stress

B. Seborrheic Eczema

• Flaking skin or dandruff
• Patchy or flaky white or yellow scales on greasy skin
• Burning or itching
• Triggers include: stress, hormonal changes, weather, harsh hair products

Management Strategies

A. General Measures for Both Atopic and Seborrheic Eczema

• Avoid known triggers and irritants
• Maintain a regular skincare routine
• Keep skin moisturised with emollients
• Use gentle, nonsoap cleansers

B. Management of Atopic Eczema

• Emollients (Moisturisers): Apply frequently to hydrate and protect skin.
• Topical Corticosteroids: Reduce inflammation and itching.
• Antihistamines: Help reduce nighttime itching.
• Other treatments: Topical calcineurin inhibitors, phototherapy, systemic medications for severe cases.

C. Management of Seborrheic Eczema

• Medicated Shampoos: Containing ketoconazole, selenium sulfide, or pyrithione zinc.
• Topical Antifungal Creams: Help reduce Malassezia yeast.
• Topical Corticosteroids: Used intermittently to control inflammation.

NICE Guidelines for Management in the UK

The NICE (National Institute for Health and Care Excellence) Clinical Knowledge Summaries (CKS) provide management guidelines for eczema in the UK. Access these guidelines via the official NICE website: https://cks.nice.org.uk/topics/eczema-atopic/

References

1. National Eczema Association. (n.d.). Types of Eczema. Retrieved from https://nationaleczema.org/eczema/types-of-eczema/

2. NHS. (n.d.). Atopic Eczema: Symptoms, Causes, and Treatments. Retrieved from https://www.nhs.uk/conditions/atopic-eczema/

3. National Eczema Association. (n.d.). Seborrheic Dermatitis: A Type of Eczema. Retrieved from https://nationaleczema.org/eczema/types-of-eczema/seborrheic-dermatitis/

4. Medical News Today. (n.d.). Seborrheic Dermatitis vs. Eczema: Key Differences. Retrieved from https://www.medicalnewstoday.com/articles/seborrheic-dermatitis-vs-eczema#summary

5. Xu, S., Immaneni, S., Hazen, G. B., et al. (2019). The burden of atopic dermatitis in the United States: A review of the literature. International Journal of Women’s Dermatology, 5(4), 246-256. Retrieved from https://pmc.ncbi.nlm.nih.gov/articles/PMC6399565/

6. National Institute for Health and Care Excellence (NICE). (2021). Atopic Eczema: Clinical Knowledge Summary. Retrieved from https://cks.nice.org.uk/topics/eczema-atopic/