76: Vitiligo Flashcards
What is vitiligo and how is it characterized?
Vitiligo is an acquired skin disease characterized by progressive loss of melanocytes, leading to well-defined milky-white macules that may also include white hairs or poliosis.
At what age does vitiligo typically begin and how does its prevalence change with age?
Vitiligo can begin at any age but usually starts before the third decade of life. Almost half of patients present before the age of 20 years, and a third before 12 years. The prevalence of vitiligo gradually increases with age.
What are the psychological impacts of vitiligo on patients?
Vitiligo is often psychologically devastating for patients, significantly impacting their quality of life. Patients may experience mental impairment similar to that seen in conditions like psoriasis and atopic dermatitis.
What are the common clinical features and presentation patterns of vitiligo?
Vitiligo lesions are asymptomatic, white, nonscaly macules and patches with distinct margins that fluoresce under a Wood lamp. They can involve any part of the body, usually with a symmetrical distribution. Initial sites often include the face, acral, and genital areas.
What are the different variants of vitiligo and their characteristics?
Variant | Characteristics |
|————————-|———————————————————————————|
| Segmental vitiligo | Affects only one side of the body, tends to occur earlier in life. |
| Acrofacial vitiligo | More common in adults, typically involves hands, feet, and face, may evolve to generalized vitiligo. |
| Vitiligo universalis | Rare form affecting greater than 80% of body surface area, usually seen in adults.
How does the age of onset of vitiligo differ between the segmental variant and the generalized form?
The segmental variant of vitiligo tends to occur earlier in life, often before the age of 12, while the generalized form usually starts before the third decade of life. This difference in age of onset may influence patient management strategies.
What are the clinical features of vitiligo lesions?
Vitiligo lesions are characterized as asymptomatic, white, nonscaly macules and patches with distinct margins. The presentation varies by form: 1. Acrofacial vitiligo: Involves the hands, feet, and face, often evolving to generalized vitiligo. 2. Vitiligo universalis: Affects greater than 80% of the body surface area and is typically seen in adults.
Discuss the historical references to vitiligo and their significance.
Historical references to vitiligo date back to 1500 BC, with mentions in the Ebers Papyrus and the Bible. These texts describe skin diseases affecting color, indicating that vitiligo was recognized as a condition that could render individuals unclean.
What is the Koebner phenomenon in relation to vitiligo?
The Koebner phenomenon is an isomorphic response where depigmentation occurs readily at the site of skin trauma in patients with active vitiligo.
What are the characteristics of segmental vitiligo?
Segmental vitiligo is seen in 10-15% of patients and is characterized by unilateral and segmental or block-shaped distribution of lesions. It typically involves a single contiguous segment and often shows early involvement of the follicular melanocyte reservoir, resulting in poliosis.
What is the significance of the VIDA score in vitiligo?
The VIDA score is a 6-point scale developed to assess and monitor vitiligo activity. It defines active vitiligo as the spread of existing lesions or the onset of new lesions.
What are some disease associations with vitiligo?
Vitiligo is associated with an increased incidence of several autoimmune diseases, including type 1 diabetes, autoimmune thyroiditis, pernicious anemia, Addison disease, lupus, and alopecia areata.
What are the competing hypotheses regarding the etiology of vitiligo?
The etiology of vitiligo includes several competing hypotheses: 1. Autoimmune hypothesis: CD8+ T cells target and destroy melanocytes. 2. Cellular stress hypothesis: Cellular stress causes degeneration of melanocytes. 3. Chemical toxicity hypothesis: Chemical toxicity leads to melanocyte death. 4. Neural changes hypothesis: Neural changes affect melanocyte function.
A 25-year-old patient with vitiligo reports rapid progression of depigmentation after a minor skin injury. What phenomenon is likely responsible?
The Koebner phenomenon, or isomorphic response, is likely responsible. It occurs when depigmentation develops at the site of skin trauma in patients with active vitiligo.
A patient with vitiligo is concerned about developing other autoimmune diseases. What tests should be recommended?
Testing for TSH is recommended to rule out autoimmune thyroid disease, as up to 20% of vitiligo patients have at least one additional autoimmune disease.
What is the significance of the Koebner phenomenon in assessing vitiligo disease activity?
The Koebner phenomenon indicates that depigmentation occurs readily at the site of skin trauma in patients with active vitiligo. This response is used as a marker of disease activity.
How does the presence of trichrome vitiligo relate to disease activity?
Trichrome vitiligo is characterized by the blurring of lesional borders due to a hypopigmented zone between depigmented and normally pigmented skin. This condition is associated with active, rapidly spreading vitiligo.
What are the implications of the VIDA score in monitoring vitiligo?
The VIDA score is a 6-point scale developed to assess and monitor vitiligo activity, providing a quantifiable measure of disease progression.
What autoimmune diseases are commonly associated with vitiligo?
Vitiligo is associated with an increased incidence of several autoimmune diseases, including type 1 diabetes, autoimmune thyroiditis, pernicious anemia, Addison disease, lupus, and alopecia areata.
What are the potential complications associated with vitiligo?
Complications of vitiligo can include sensorineural hearing loss, ocular abnormalities, and syndromes like Vogt-Koyanagi-Harada syndrome and Alezzandrini syndrome.
Discuss the competing hypotheses regarding the etiology of vitiligo and their clinical implications.
The etiology of vitiligo is primarily understood as an autoimmune disease where CD8+ T cells target and destroy melanocytes. Other hypotheses suggest that cellular stress, chemical toxicity, and neural changes may also contribute.
What role do CD8+ T cells play in the pathogenesis of vitiligo?
CD8+ T cells are critical immune effectors that infiltrate the lesional epidermis and mediate cytotoxicity, leading to the destruction of melanocytes in vitiligo patients.
What is the convergence theory in relation to vitiligo?
The convergence theory suggests that multiple hypotheses regarding the pathogenesis of vitiligo may synergize to cause the disease.
How does the segmental variant of vitiligo differ from other forms?
The segmental variant of vitiligo rarely follows dermatomes and often crosses these zones, resulting from an autoimmune predisposition combined with melanocyte mutations.
