Model Answer
0 min readIntroduction
Vitiligo is a common acquired pigmentary disorder characterized by the loss of melanocytes, resulting in circumscribed areas of depigmentation. It affects approximately 0.5-2% of the world’s population, irrespective of sex, race, or geographic location. The clinical presentation often begins with small, milk-white macules that gradually enlarge and coalesce. Understanding the etiology, associated features, classification, and natural history of vitiligo is crucial for effective management and patient counseling. This response will address the specific clinical scenario presented, providing a comprehensive dermatological assessment.
(i) Diagnosis
Based on the described clinical presentation – asymptomatic, depigmented, chalky white macules and patches with no inflammation, particularly over the face and around body orifices – the most likely diagnosis is Vitiligo. The distribution pattern is highly suggestive, as these areas are commonly affected in vitiligo. Other differential diagnoses, such as pityriasis alba, post-inflammatory hypopigmentation, and chemical leukoderma, are less likely given the lack of inflammation and the characteristic distribution.
(ii) Associated Findings
Vitiligo is often associated with several findings, including:
- Koebner phenomenon: The development of vitiligo lesions at sites of trauma (e.g., scratches, burns).
- Trichrome hypopigmentation: Intermediate zones of hypopigmentation between the fully depigmented areas and normal skin.
- Salt-and-pepper hair: Premature graying of hair in affected areas.
- Associated autoimmune diseases: A higher prevalence of autoimmune conditions such as Hashimoto's thyroiditis, Graves' disease, Addison's disease, type 1 diabetes mellitus, and pernicious anemia. Approximately 15-25% of patients with vitiligo have an associated autoimmune disease (based on knowledge cutoff 2023).
- Ocular involvement: Uveitis, chorioretinitis, and optic nerve involvement can occur, though less common.
- Periorificial involvement: As noted in the case, involvement around body orifices (mouth, nose, eyes, genitalia) is common.
(iii) Classification of Vitiligo
Vitiligo is classified based on its pattern of depigmentation. The most recent and widely accepted classification system (2011) categorizes vitiligo into the following types:
| Type | Description |
|---|---|
| Generalized Vitiligo | Depigmentation is widespread and affects many areas of the body. It can be symmetrical or asymmetrical. |
| Segmental Vitiligo | Depigmentation is confined to a dermatomal or non-dermatomal segment of the body. It typically progresses rapidly for a limited period and then stabilizes. |
| Localized Vitiligo | Includes focal vitiligo (one or a few discrete macules) and acrofacial vitiligo (affecting the acral areas – hands, feet, face). |
| Universal Vitiligo | Almost complete depigmentation of the skin. |
| Mixed Vitiligo | Combination of features from different types. |
The case described most likely represents Generalized Vitiligo, given the widespread distribution on the face and body.
(iv) Clinical Course of the Disease
The clinical course of vitiligo is variable and unpredictable. It typically follows a pattern of:
- Initial phase: Slowly progressive development of new lesions over months to years.
- Stationary phase: The disease stabilizes, and no new lesions appear.
- Repigmentation phase: Spontaneous repigmentation can occur, often starting from the periphery of the lesions. This is more common in patients with limited disease and in areas exposed to sunlight.
- Progression can be intermittent: Periods of activity and quiescence are common.
The prognosis of vitiligo is difficult to predict. Factors influencing prognosis include the extent and location of depigmentation, the patient's age, and the presence of associated autoimmune diseases. Segmental vitiligo tends to have a more limited and predictable course compared to generalized vitiligo. Psychological impact can be significant, and patients may experience anxiety, depression, and social stigma.
Conclusion
In conclusion, the clinical presentation strongly suggests vitiligo, likely generalized vitiligo. Associated findings, such as the Koebner phenomenon and autoimmune associations, should be considered during evaluation. The disease course is variable, and management focuses on slowing progression, promoting repigmentation, and addressing the psychological impact. A thorough understanding of the classification and clinical course is essential for providing comprehensive patient care.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.