Module 2: Inflammatory Skin Disorders

Eczema (Dermatitis)

Eczema (also known as dermatitis) refers to a group of inflammatory skin conditions characterized by itching, erythema, and scaling. It can be acute or chronic and may present differently depending on the subtype.

Atopic Dermatitis

Definition: A chronic, relapsing inflammatory skin condition commonly seen in children, often associated with a personal or family history of atopy (asthma, allergic rhinitis).

Clinical Features

Fig. 2.1: Images of eczema

1. Eczema on the face (bilateral cheek eczema)
2. Lichenified eczema on the knees (reverse pattern)
3. Excoriated acute eczema (atopic eczema)

Images sourced from DermNet.

• Age-related distribution:

  • Infants: Face, scalp, extensor surfaces

  • Children: Flexural areas (elbows, knees)

  • Adults: Hands, eyelids, neck

• Lesions:

  • Erythematous, scaly patches

  • Lichenification in chronic cases

  • Excoriations due to scratching

• Associated features:

  • Xerosis (dry skin)

  • Dennie-Morgan infraorbital folds

  • Keratosis pilaris

History-taking Tips

• Onset and duration

• Family history of atopy

• Triggering factors (heat, sweat, allergens)

• Sleep disturbance due to itching

Management

• General: Emollients, avoidance of triggers

• Topical: Corticosteroids, calcineurin inhibitors

• Systemic: Antihistamines, immunomodulators (in severe cases)

• Education: Skin care routines, flare prevention

Contact Dermatitis

Definition: Inflammation of the skin due to direct contact with an irritant or allergen.

Types:

• Irritant Contact Dermatitis: Non-immunologic, caused by repeated exposure to irritants (e.g., soaps, detergents).
  [Update 2025 CDC/BASHH]: Patch testing is advised for recurrent or occupational cases; avoid corticosteroids in chronic irritant dermatitis.

• Allergic Contact Dermatitis: Delayed hypersensitivity reaction to allergens (e.g., nickel, fragrances, latex).

Clinical Features

Fig. 2.2: Contact dermatitis

• Localized erythema, vesicles, and scaling

• Sharp demarcation of the affected area

• Chronic exposure may lead to lichenification

History-taking Tips

• Occupational exposure

• Recent use of new products (cosmetics, gloves)

• Timing of rash relative to exposure

• Patch testing history (if available)

Management

• Avoidance: Identify and eliminate the offending agent

• Topical: Steroids for inflammation

• Barrier protection: Gloves, protective creams

• Referral: For patch testing if the diagnosis is unclear

Seborrhoeic Dermatitis

Definition: A chronic, relapsing dermatitis affecting sebaceous gland-rich areas, often associated with Malassezia yeast overgrowth.

Clinical Features

Fig. 2.3: Seborrhoeic dermatitis

1. Infantile seborrhoeic dermatitis (antecubital fossa)
2. Cheek and nasolabial fold seborrhoeic dermatitis

Images sourced from DermNet.

• Greasy, yellowish scales over erythematous base

• Common sites: Scalp, nasolabial folds, eyebrows, chest

• May be associated with Parkinson’s disease or HIV

History-taking Tips

• Fluctuating course, often worse in winter

• Scalp involvement (dandruff)

• Associated systemic conditions

Management

• Topical antifungals: Ketoconazole shampoo or cream

• Mild corticosteroids: For inflammation

• Scalp care: Medicated shampoos (selenium sulphide, zinc pyrithione)

Comparative Overview of Eczema Subtypes

Table 2.1: Comparative Overview of Eczema Subtypes

Subtype	Age Group	Distribution	Triggers	Clinical Features	Management
Atopic Dermatitis	Infants, Children, Adults	Infants: face/extensors; Children: flexures; Adults: hands, eyelids	Heat, sweat, allergens, irritants	Dry skin, erythema, lichenification, excoriations	Emollients, topical steroids, antihistamines
Contact Dermatitis	All ages	Localized to the area of contact	Irritants (soaps, detergents), allergens (nickel, latex)	Erythema, vesicles, scaling, sharp demarcation	Avoid triggers, topical steroids, barrier protection
Seborrhoeic Dermatitis	Infants, Adults	Scalp, nasolabial folds, eyebrows, chest	Malassezia yeast, stress, cold weather	Greasy scales, erythema, chronic relapsing	Antifungal creams/shampoos, mild steroids

Fig. 2.4: Comparative illustration of eczema subtypes

Fig. 2.5: Comparative distribution of eczema subtypes

Highlights:

• Atopic Dermatitis (Infant): Face, extensors, trunk, hands, feet.
  Contact Dermatitis: Hands, forearms, neck—localized to exposure.
  [Update 2025 CDC/BASHH]: Patch testing is advised for recurrent or occupational cases; avoid corticosteroids in chronic irritant dermatitis.

• Seborrhoeic Dermatitis: Scalp, eyebrows, chest—sebaceous-rich areas.
  [Update 2025 CDC/BASHH]: Ketoconazole shampoo remains first-line; consider HIV screening in severe cases.

Dermatological Terminology

Table 2.2: Dermatological Terminology and Descriptions

• Macule: Flat, non-palpable discoloration <1 cm.

• Papule: Raised, solid lesion <1 cm.

• Plaque: Raised, flat-topped lesion >1 cm.

• Vesicle: Fluid-filled blister <1 cm.

• Pustule: Pus-filled lesion.

• Nodule: Larger, deeper lesion.

• Scale: Flaky keratin debris.

• Crust: Dried serum or exudate.

• Erosion/Ulcer: Loss of epidermis/dermis.

• Excoriation: Linear erosion due to scratching.

Clinical Vignettes

Vignette 1: The Itchy Child

Patient: 6-year-old boy
Complaint: Persistent itching over the flexural areas of arms and legs
History Highlights:

• Symptoms began 3 months ago, worsening at night.

• Mother reports dry skin since infancy.

• Family history of asthma and allergic rhinitis.

• No recent travel or new skincare products.

• Uses over-the-counter moisturizers inconsistently.

Discussion Points:

• Consider atopic dermatitis.

• Explore environmental triggers and skin care routine.

• Ask about sleep disturbance and school impact.

Vignette 2: The Red Face

Patient: 32-year-old woman
Complaint: Facial redness and burning sensation
History Highlights:

• Onset 2 weeks ago, worsened with sun exposure.

• Uses new anti-aging cream with retinoids.

• No systemic symptoms.

• No prior history of skin disease.

Discussion Points:

• Consider contact dermatitis or rosacea.

• Ask about cosmetic use, sun exposure, and occupation.

• Explore photosensitivity and autoimmune screening if needed.

Vignette 3: The Painful Leg

Patient: 58-year-old man
Complaint: Painful, red swelling on the lower leg
History Highlights:

• Sudden onset 2 days ago, associated with fever.

• Diabetic for 10 years, poorly controlled.

• No trauma, but scratches from gardening.

• On oral antibiotics from GP with minimal improvement.

Discussion Points:

• Consider cellulitis.

• Ask about systemic symptoms and comorbidities.

• Explore risk of complications and need for hospitalization.

Vignette 4: The Blistering Rash

Fig. 2.6: Allergic contact dermatitis

Patient: 24-year-old woman
Complaint: Blisters on hands and forearms
History Highlights:

• Appeared after hiking trip, exposed to wild plants.

• Itchy and oozing lesions.

• No prior similar episodes.

• No systemic symptoms.

Discussion Points:

• Consider allergic contact dermatitis.

• Ask about exposure history and timing.

• Discuss patch testing and avoidance strategies.

Vignette 5: The Recurrent Spots

Fig. 2.7: Acne

Image sourced from DermNet.

Patient: 19-year-old male
Complaint: Recurrent pustules on face and back
History Highlights:

• Present for 2 years, worsens with stress.

• Tried multiple topical treatments with limited success.

• No systemic symptoms.

• Concerned about scarring and social impact.

Discussion Points:

• Consider acne vulgaris.

• Ask about treatment adherence, diet, and psychosocial impact.

• Discuss long-term management and referral options.

Acne Vulgaris: Therapeutic Algorithm

Step 1: Assess Severity

• Mild: Comedonal acne

• Moderate: Papulopustular acne

• Severe: Nodulocystic or conglobata

Step 2: Initiate Treatment

Table 2.3: Treatment of Acne by Severity

Severity	First-Line Treatment	Alternatives	Notes
Mild	Topical retinoid (e.g., adapalene) + Benzoyl peroxide	Topical azelaic acid	Avoid monotherapy with topical antibiotics
Moderate	Topical retinoid + Benzoyl peroxide + Topical antibiotic (e.g., clindamycin)	Oral doxycycline/minocycline	Combine oral antibiotics with topical agents
Severe	Oral isotretinoin (monotherapy)	Hormonal therapy (females) + oral antibiotics	Monitor liver function, lipids, and pregnancy status

Step 3: Adjuncts

• Non-comedogenic skincare

• Sun protection

• Hormonal evaluation (e.g., PCOS in females)

Step 4: Follow-Up

• Reassess in 6–8 weeks

• Monitor for side effects

• Consider referral for scarring or psychological distress

Psoriasis

Table 2.4: Classification of Psoriasis and Diagnostic Features

Psoriasis Type	Clinical Features	Common Sites	Key Diagnostic Features
Chronic Plaque	Well-demarcated erythematous plaques with silvery-white scales	Elbows, knees, scalp, lower back	PASI used to assess severity
Guttate	Small, drop-like scaly papules	Trunk, limbs	Often post-infectious onset
Pustular	Sterile pustules, localized or generalized	Palms, soles, generalized	Clinically distinct pustules
Inverse (Flexural)	Smooth, shiny erythematous plaques in folds	Axillae, groin, flexures	Often misdiagnosed as fungal/intertrigo
Scalp	Thick scales, erythematous plaques extending beyond hairline	Scalp	May cause temporary hair loss
Nail Psoriasis	Pitting, onycholysis, discoloration, subungual hyperkeratosis	Fingernails, toenails	Key indicator of systemic involvement
Psoriatic Arthritis	Joint pain, swelling (often asymmetric), dactylitis, enthesitis	Peripheral/axial joints + nails	RF and anti-CCP negative, MRI/X-rays supportive

Chronic Plaque Psoriasis

Diagnosis

• Clinical Features:

  • Well-demarcated, erythematous plaques with silvery-white scales.

  • Commonly affects elbows, knees, scalp, and lower back.

Fig. 2.8: Well-circumscribed plaques of psoriasis

Image sourced from DermNet.

• Investigations:

  • Usually clinical; biopsy may be done to rule out other dermatoses.

  • Assess severity using PASI (Psoriasis Area and Severity Index) or BSA (Body Surface Area).

Management

• Topical Therapies:

  • Corticosteroids: First line for mild to moderate disease.

  • Vitamin D analogues: Calcipotriol, calcitriol – slow keratinocyte proliferation.

  • Retinoids: Tazarotene – normalize epidermal differentiation.

  • Calcineurin inhibitors: Tacrolimus, pimecrolimus – for sensitive areas.

• Phototherapy:

  • UVB narrowband or PUVA for moderate disease.

• Systemic Therapies:

  • Methotrexate, Cyclosporine, Acitretin – for severe or refractory cases.

  • Biologics: TNF-α inhibitors (e.g., adalimumab), IL-17/IL-23 inhibitors (e.g., secukinumab, guselkumab)[1].

Scalp and Genital Psoriasis

[Update 2025 CDC/BASHH]: IL-17 and IL-23 inhibitors are preferred for biologic-naive patients with moderate-to-severe disease.

Diagnosis

• Scalp Psoriasis:

  • Thick scales over erythematous plaques, often extending beyond the hairline.

  • May cause hair loss due to inflammation.

Fig. 2.9: Scalp psoriasis

• Genital Psoriasis:
  Smooth, shiny erythematous plaques; often misdiagnosed as fungal or contact dermatitis.

• May involve flexural areas (inverse psoriasis).

Management

• Scalp Psoriasis:

  • Medicated shampoos: Salicylic acid, coal tar, ketoconazole.

  • Topical corticosteroids: Foam or solution formulations.

  • Vitamin D analogues: Calcipotriol scalp solution.

• Genital Psoriasis:

  • Low-potency corticosteroids: Hydrocortisone.

  • Calcineurin inhibitors: Tacrolimus, pimecrolimus – preferred for thin skin.

  • Avoid irritants: Fragrance-free products, gentle hygiene practices.

Psoriatic Arthritis

Diagnosis

• Clinical Features:

  • Joint pain, stiffness, swelling – often asymmetric.

  • Nail changes: pitting, onycholysis.

  • Enthesitis and dactylitis may be present.

Fig. 2.10: Psoriatic arthritis (Source: Wikipedia)

• Investigations:

  • X-rays/MRI: Joint damage, enthesitis.

  • RF and anti-CCP: Usually negative (helps differentiate from RA).

  • Joint aspiration: Rule out gout or infection[3].

Management

• NSAIDs: For mild joint symptoms.

• DMARDs:

  • Methotrexate, Leflunomide, Sulfasalazine – slow disease progression.

• Biologics:

  • TNF-α inhibitors, IL-17/IL-23 inhibitors – for moderate to severe disease.

• Lifestyle:

  • Weight management, smoking cessation, physical therapy.

Fig. 2.11: Psoriasis types

Treatment Algorithm for Psoriasis

Table 2.5: Summary of Clinical Management of Psoriasis

Psoriasis Type	First-line Treatment	Second-line/ Systemic Therapies	Notes
Chronic Plaque	Topical corticosteroids, Vitamin D analogues	Phototherapy (NB-UVB), Methotrexate, Cyclosporine, Acitretin	Biologics for moderate-severe or refractory cases
Guttate	Typically self-limiting; topical steroids or UVB phototherapy if needed	Systemic for severe or persistent cases	Screen for streptococcal infection
Pustular	Topical corticosteroids, systemic retinoids	Cyclosporine, Methotrexate, Biologics	Monitor for systemic symptoms
Inverse	Low potency topical corticosteroids, calcineurin inhibitors	Systemic if extensive or refractory	Avoid irritants and friction
Scalp	Medicated shampoos (salicylic acid, coal tar), topical corticosteroid foam or solution, vitamin D analogues	Phototherapy, systemic agents if severe	Avoid hair-damaging agents
Nail Psoriasis	Topical high-potency corticosteroids, vitamin D analogues	Methotrexate, Biologics if severe	Nail matrix penetration poor; systemic preferred in severe cases
Psoriatic Arthritis	NSAIDs for mild symptoms	DMARDs (methotrexate, leflunomide), Biologics (TNF, IL-17, IL-23 inhibitors)	Early referral to rheumatology recommended

Summary: Treatment Algorithm for Psoriasis

1. Assess severity with PASI, DLQI, and PGA score.

2. Identify high-impact sites (nails, scalp, face, palms/soles, genitals).

3. Start with topical therapies for mild disease, considering site.

4. For moderate to severe disease or high-impact sites:

   • Use phototherapy (NB-UVB preferred).

   • Initiate systemic therapy (methotrexate, cyclosporine, acitretin).

5. If inadequate response or contraindications, move to biologics targeting:

   • TNF inhibitors (adalimumab, etanercept)

   • IL-17 inhibitors (secukinumab, ixekizumab)

   • IL-23 inhibitors (guselkumab, risankizumab)

6. For nail psoriasis impacting function or refractory to topical therapy, consider systemic or biologic treatment.

7. Joint symptoms require NSAIDs initially, then DMARDs and biologics based on severity, with rheumatology referral.

8. Lifestyle support includes smoking cessation, weight control, and physical therapy for joint disease.

Psoriasis: Clinical Case Vignettes

Vignette 1: Chronic Plaque Psoriasis

Fig. 2.12: Chronic plaque psoriasis

Patient: 45-year-old male
Complaint: Persistent scaly plaques on elbows and knees
History:

• Lesions present for 6 months, gradually increasing.

• No joint pain or systemic symptoms.

• Family history of psoriasis.

• Tried moisturizers with minimal improvement.

Examination:

• Well-demarcated erythematous plaques with silvery scales on extensor surfaces.

• No nail changes.

Discussion Points:

• Diagnosis: Chronic plaque psoriasis

• Severity assessment: PASI score

• Management: Topical corticosteroids + vitamin D analogues

Clinical Notes

Therapeutic algorithms for psoriasis, designed for clinical-year MBBS students, are based on current international guidelines (e.g., AAD, NICE, BASHH, CDC).

Step 1: Assess Severity

• Mild: <5% BSA

• Moderate: 5–10% BSA

• Severe: >10% BSA or significant impact on QoL

Step 2: Initiate Treatment

Severity	First-Line Treatment	Alternatives	Notes
Mild	Topical corticosteroids + Vitamin D analogues (e.g., calcipotriol)	Calcineurin inhibitors (sensitive areas)	Use emollients regularly
Moderate	Phototherapy (NB-UVB)	Topical + systemic (e.g., methotrexate)	Consider PASI score for monitoring
Severe	Systemic therapy: Methotrexate, Cyclosporine, Acitretin	Biologics: TNF-α, IL-17, IL-23 inhibitors	Screen for TB, hepatitis before biologics

Step 3: Special Sites

• Scalp: Medicated shampoos + topical steroids

• Genital: Low-potency steroids or tacrolimus

• Nails: Systemic therapy often required

Step 4: Follow-Up

• Monitor for adverse effects

• Screen for comorbidities (e.g., PsA, metabolic syndrome)

• Consider dermatology referral for biologics

Vignette 2: Scalp and Genital Psoriasis

Patient: 28-year-old woman
Complaint: Itchy scalp and red patches in the genital area
History:

• Scalp scaling for 3 months worsens with stress.

• Genital discomfort, misdiagnosed as a fungal infection.

• No joint pain.

Examination:

• Thick scales on scalp extending beyond hairline.

• Smooth erythematous plaques in the vulval region.

Discussion Points:

• Diagnosis: Scalp and genital psoriasis

• Management: Ketoconazole shampoo, low-potency steroids, tacrolimus cream

Vignette 3: Psoriatic Arthritis

Patient: 52-year-old man
Complaint: Joint pain and stiffness in fingers
History:

• Morning stiffness >30 minutes, improves with activity.

• History of psoriasis for 10 years.

• Nail pitting and onycholysis are present.

Examination:

• Swollen PIP joints, dactylitis in one finger.

• Psoriatic plaques on knees.

Discussion Points:

• Diagnosis: Psoriatic arthritis

• Investigations: RF negative, X-ray shows joint erosion

• Management: NSAIDs, methotrexate, consider biologics

Multiple Choice Questions

Tap an answer to check yourself — the correct option and an explanation appear once you choose.

Q1 Which of the following is the most characteristic lesion of chronic plaque psoriasis?

• A Vesicles on flexural surfaces
• B Well-demarcated erythematous plaques with silvery scales
• C Greasy scales on scalp and chest
• D Hyperpigmented macules on trunk

Q2 Which topical agent is commonly used in the treatment of scalp psoriasis?

• A Tacrolimus ointment
• B Calcipotriol scalp solution
• C Hydrocortisone cream
• D Salicylic acid lotion

Q3 Which nail finding is most commonly associated with psoriatic arthritis?

• A Beau’s lines
• B Koilonychia
• C Nail pitting
• D Splinter haemorrhages

Q4 Which investigation helps differentiate psoriatic arthritis from rheumatoid arthritis?

• A ESR
• B Rheumatoid factor
• C ANA
• D CRP

Q5 Which of the following is a first-line systemic treatment for moderate to severe plaque psoriasis?

• A Isotretinoin
• B Methotrexate
• C Prednisolone
• D Hydroxychloroquine