Comprehensive Study Notes on Vulval Dermatoses and Gynaecological Pathology

Lichen Sclerosus (LS)

Lichen sclerosus is a chronic inflammatory vulval dermatosis characterized by its unique morphological presentation and significant long-term implications. Key diagnostic buzzwords include a persistent itch as the primary symptom, a loss of normal anatomical architecture through scarring and resorption, and a characteristic "figure of 8" pattern. This condition carries a lifetime incidence of approximately $3\%$, and patients face a specific risk of developing Squamous Cell Carcinoma (SCC) at a rate of $3-5\%$. Treatment fundamentally relies on the use of ultra-potent topical steroids.

Etiology and Autoimmune Associations

Lichen sclerosus is an immune-mediated chronic inflammatory disease. It is strongly associated with other autoimmune conditions, particularly thyroid disease such as Hashimoto's thyroiditis. Genetic studies have identified an association with HLA DQ7, which is the most common genetic marker found in affected individuals. Other documented autoimmune associations include vitiligo, alopecia areata, autoimmune gastritis leading to pernicious anaemia, Type 1 diabetes mellitus, and myasthenia gravis.

Clinical Features and Symptoms

The primary symptom reported by patients is intense itching, though soreness, dyspareunia (painful intercourse), dysuria (painful urination), and constipation (due to perianal involvement) are also common. Clinical signs include skin that appears white, thin, and porcelain-like. The loss of architecture is a hallmark of the disease, manifesting as the fusion of the labia minora, phimosis of the clitoral hood, labial resorption, and narrowing of the vaginal introitus. The "figure of 8" pattern refers to the specific involvement of both the vulva and the perianal area.

Diagnosis and Histology

Diagnosis is usually clinical based on history and typical appearance. However, a biopsy is mandatory if there is diagnostic uncertainty, atypical features, treatment failure, or concern for malignancy. Histologically, LS is defined by a three-layer structure: a thin top layer (epidermal atrophy), a thick and dense middle layer caused by scarring (subepidermal hyalinisation of collagen), and a deeper layer showing inflammation (lymphocytic infiltration).

Management and Treatment Tiers

The first-line medical intervention is an ultra-potent steroid, specifically Clobetasol propionate $0.05\%$ ointment. The standard regimen involves applying one finger-tip-unit (FTU) nightly for $3$ months, followed by a tapering schedule (e.g., alternate nights, then twice weekly for maintenance). If Clobetasol is not tolerated, Mometasone furoate $0.1\%$ ointment is the recommended alternative. Adjunctive measures are vital and include the use of regular emollients for barrier protection and hydration, gentle skin care, and the strict avoidance of irritants like soaps, perfumed products, and wet wipes. For resistant cases, calcineurin inhibitors such as tacrolimus or pimecrolimus may be used. Retinoids are another option, though they must be stopped $1$ month before conception.

Pregnancy and Postpartum Considerations

During pregnancy, $44\%$ of patients experience an improvement in symptoms; however, Clobetasol should not be discontinued. Safety data indicates no increased risk of congenital anomalies, preterm birth, fetal death, or low Apgar scores. A Caesarean section is only indicated if there is a severely narrowed introitus. Postpartum, $60\%$ of patients may experience a worsening of the condition. In breastfeeding mothers, the hypoestrogenic state (Genitourinary syndrome of lactation) may necessitate low-dose vaginal oestrogen applied to the introitus and perineum.

Lichen Planus (LP)

Lichen planus is an inflammatory autoimmune (T-cell mediated) disorder of unknown cause that affects both skin and mucous membranes. It is notably red, painful, and erosive. Unlike Lichen Sclerosus, Lichen Planus frequently involves the vagina. A high-yield clinical association is the Vulvo-Vaginal-Gingival (VVG) syndrome, which involves the vulva, vagina, and the gums (gingiva).

Clinical Features and Subtypes

Symptoms of LP include soreness, burning, dyspareunia, postcoital bleeding (PCB), and blood-stained discharge. While itching occurs, pain is the dominant symptom. There are three primary subtypes:

1. Erosive Lichen Planus: The most common symptomatic subtype, featuring bright red erosions, raw friable mucosa that bleeds easily, and Wickham's striae (white lacy lines) at the edges of the erosions.
2. Classical Lichen Planus: Characterized by small purple papules; may be asymptomatic.
3. Hypertrophic Lichen Planus: A rare form presenting with thickened, warty plaques, often perianal. This subtype carries a higher risk of SCC and can mimic malignancy.

Examination Findings and Vaginal Involvement

A differentiating factor for LP is vaginal involvement, which does not occur in LS. This leads to vulval erosions extending into the vagina, vaginal adhesions, and vaginal stenosis (shortened vagina). Wickham's striae may also be visible on the skin or mucosal surfaces.

Histology and Diagnosis

Histological examination of LP typically shows irregular "saw-toothed" acanthosis, hypergranulosis, basal cell degeneration, and a band-like lymphocytic infiltrate in the upper dermis. Biopsy is indicated for diagnostic uncertainty, atypical features, or treatment failure.

Management Regimens

First-line treatment is Clobetasol propionate $0.05\%$ ointment, applied twice daily initially until controlled, then reduced for maintenance. If the vagina is involved, patients may require steroid suppositories or steroids applied via a vaginal dilator. Severe flares may be treated with a short course of oral prednisolone. Long-term maintenance is usually required to prevent scarring and stenosis.

Vulval Eczema (Dermatitis)

Vulval eczema is a common cause of vulval pruritus and is as inflammatory condition often referred to as dermatitis. It can be categorized into four types:

1. Atopic Eczema: Associated with asthma, hay fever, and food allergies.
2. Irritant Contact Dermatitis: The most common form, caused by external triggers like soaps, wipes, urine, or sweat.
3. Allergic Contact Dermatitis: A Type IV delayed hypersensitivity reaction (occurring $48-72\,h$ after exposure) to substances like fragrances, preservatives, or local anaesthetics.
4. Seborrhoeic Eczema: Affects sebaceous areas and may present with greasy scales.

Clinical Presentation and Findings

The most important step in management is the identification and avoidance of the irritant or allergen. Symptoms include intense itching, soreness, and burning. Examination often reveals poorly defined erythema, dry scaling skin, excoriations, and fissures. Chronic scratching leads to Lichen Simplex Chronicus, characterized by thickened, leathery skin (lichenification).

Management of Eczema

Treatment involves moderate (Clobetasone butyrate $0.05\%$) or potent (Mometasone furoate $0.1\%$) topical steroid ointments applied nightly for $4$ weeks. Regular emollients are used as soap substitutes and barrier protection. Sedating antihistamines (e.g., hydroxyzine) may be used at night for severe itching. A critical safety warning is issued for paraffin-based emollients, which represent a significant fire risk; patients must avoid naked flames and smoking when these products are on dressings or clothing.

Vulval Psoriasis

Vulval psoriasis is a chronic inflammatory epidermal disease affecting approximately $2\%$ of the population. Genital involvement occurs in over $60\%$ of psoriasis patients during their lifetime. It is often more severe in individuals with HIV infection.

Visual and Clinical Indicators

Psoriasis presents as well-demarcated, brightly erythematous plaques that are usually symmetrical. Common sites include the outer labia majora and mons pubis. Unlike psoriasis on other parts of the body, scaling is rarely seen on the vulva due to the naturally moist environment. Fissuring and significant pain are common. Clinicians must check "hidden sites" for involvement, such as the scalp, nails, umbilicus, elbows, and knees.

Management Protocols

First-line therapy is a moderate or potent topical steroid (e.g., Mometasone furoate $0.1\%$) applied nightly for $4$ weeks. Alternatives include Tacrolimus $0.1\%$ ointment (though it may sting initially) and Vitamin D analogues (though these may cause irritation). For severe or recalcitrant disease, referral to dermatology for systemic therapies like biologics or methotrexate is necessary.

Other Vulval Conditions

Plasma Cell (Zoon's) Vulvitis

This is a benign but painful condition typically seen in postmenopausal women. It presents with pruritus, burning, and dyspareunia. Histology shows a characteristic plasma cell dermal infiltration. It is often resistant to steroids and may require treatment with calcineurin inhibitors.

Vulval Candidiasis

Characterized by a "cottage cheese" discharge and satellite lesions extending from the labia majora toward the inner thighs. This presentation is also associated with intertrigo.

Extra-mammary Paget's Disease

This is a rare, preinvasive condition that is often misdiagnosed as eczema or psoriasis, leading to an average diagnostic delay of $2$ years. It may be primary or secondary to an underlying invasive cancer (remote or local). It presents as thickened, erythematous, and excoriated skin with sharp borders and red velvety margins. Biopsy reveals typical Paget cells.

Morphological Descriptors of Vulval Lesions

Proper dermatological terminology is essential for accurate documentation and diagnosis:

• Fissure: A thin hairline crack in the skin (e.g., in Psoriasis or LS).
• Excoriation: Scratch marks from itching.
• Erosion: Shallow denuded area (loss of epidermis only).
• Ulcer: Full-thickness loss of the epidermis and sometimes the dermis.
• Macule: Flat area of color change (e.g., melanosis).
• Nodule: Palpable lesion greater than $0.5\,cm$ in diameter.
• Papule: Small palpable lesion less than $0.5\,cm$ in diameter.
• Plaque: Flat, palpable lesion greater than $0.5\,cm$ that may be elevated or thickened.
• Vesicle: Fluid-filled blister less than $0.5\,cm$ in diameter.
• Lichenification: Accentuated skin markings and thickening from chronic rubbing.

Gynaecological Investigation Algorithm

A systematic approach to vulval investigations is required based on clinical presentation:

1. White Atrophic or Chronic Lesions (e.g., LS, LP, VIN): Perform a punch biopsy. Consider Thyroid Function Tests (TFTs) for LS.
2. Pigmented Lesions (changing or irregular): Perform a punch biopsy to rule out melanoma or pigmented VIN.
3. Painful Vesicles or Ulcers: Use Viral PCR from a lesion swab to test for Herpes Simplex Virus (HSV).
4. Itch with Cottage Cheese Discharge: Utilize Gram stain and culture for Candida. For recurrent cases, use fungal culture for speciation and sensitivities.
5. Secondary Bacterial Infection: Look for crusting or purulent discharge; use Gram stain and culture.
6. Allergic Contact Dermatitis: If symptoms persist after removing triggers, refer for patch testing.
7. Painless Ulcer: Consider Syphilis and perform serology (RPR/VDRL).
8. Blisters, Erosions, or Bullae: Consider autoimmune bullous diseases and perform direct immunofluorescence.

The golden rule for any persistent, suspicious, or atypical vulval dermatosis is to perform a punch biopsy.