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Fitzpatrick's Dermatology, 9th Edition (Chapter-based Decks) > 93, 94, 95: Actinic Prurigo, Hydroa Vacciniforme, Actinic Dermatitis > Flashcards

93, 94, 95: Actinic Prurigo, Hydroa Vacciniforme, Actinic Dermatitis Flashcards

1
Q

What is Actinic Prurigo (AP) and how is it characterized?

A

Actinic Prurigo (AP) is a chronic sunlight-induced pruritic eruption characterized by papules or nodules, many of which are excoriated.

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2
Q

What populations are particularly affected by Actinic Prurigo?

A

The indigenous populations of North and South America are particularly affected by Actinic Prurigo.

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3
Q

What are the common clinical presentations of Actinic Prurigo?

A

Common clinical presentations include pruritus, pain or tingling sensations, conjunctivitis, and pruritic papules or nodules.

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4
Q

What are the noncutaneous findings associated with Actinic Prurigo?

A

Noncutaneous findings include mucosal involvement, cheilitis, and conjunctivitis.

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5
Q

What are the complications associated with Actinic Prurigo?

A

Complications include mild scarring, hypopigmentation from excoriations, and primary cutaneous B-cell lymphoma.

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6
Q

What is the etiology and pathogenesis of Actinic Prurigo?

A

Etiology includes induction by ultraviolet radiation, with TNF-α overexpressed by keratinocytes.

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7
Q

What is the presumed immunologic mechanism behind worsening symptoms in winter for Actinic Prurigo?

A

Immunologic tolerance presumably develops during the summer, leading to worsening symptoms in winter.

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8
Q

What is the typical onset age for Actinic Prurigo?

A

Usually by age 10 years, with the earliest onset in Native American populations at 4 to 5 years of age.

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9
Q

What environmental factor is primarily responsible for Actinic Prurigo?

A

Ultraviolet radiation.

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10
Q

What are the clinical features that suggest Actinic Prurigo rather than Polymorphous Light Eruption (PMLE)?

A

Features include disease onset in childhood, lesions on both exposed and sun-protected skin, and persistence of lesions beyond 4 weeks.

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11
Q

What laboratory tests support the diagnosis of Actinic Prurigo?

A

Laboratory tests include ANA and ENA to exclude other forms, and HLA DR4 typing.

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12
Q

What are the common management options for Actinic Prurigo?

A

Management options include higher-potency topical corticosteroids, topical calcineurin inhibitors, and oral antihistamines.

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13
Q

What is the treatment of choice for more severe or recalcitrant cases of Actinic Prurigo?

A

Thalidomide is the treatment of choice for severe or recalcitrant cases.

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14
Q

What are the potential adverse effects of Thalidomide when used for Actinic Prurigo?

A

Potential adverse effects include drowsiness, headache, constipation, weight gain, and increased risk of thromboembolism.

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15
Q

What are the cornerstone strategies for managing Actinic Prurigo?

A

The cornerstone strategies include sun protection and avoidance strategies.

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16
Q

What is Hydroa Vacciniforme and how does it typically present in patients?

A

Hydroa Vacciniforme (HV) is a rare, chronic photodermatosis characterized by photoinduced papules and vesicles that invariably scar after healing.

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17
Q

What are the common cutaneous findings associated with Hydroa Vacciniforme?

A

Cutaneous findings include initial erythema and swelling, eruption of tender papules and vesicles, and development of permanent scars.

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18
Q

What noncutaneous findings are associated with Hydroa Vacciniforme?

A

Noncutaneous findings include oral ulcers and eye involvement.

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19
Q

What is Hydroa Vacciniforme (HV)?

A

A rare, chronic photodermatosis characterized by photoinduced papules and vesicles that invariably scar after healing.

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20
Q

What is the typical onset age for Hydroa Vacciniforme?

A

Typically occurs in childhood, often before the age of 8.

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21
Q

What are the common clinical presentations of Hydroa Vacciniforme?

A

Intense burning or stinging sensation followed by papules and vesicles after sunlight exposure, leading to scarring.

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22
Q

What are the noncutaneous findings associated with Hydroa Vacciniforme?

A

Oral ulcers and eye involvement, including conjunctival hyperaemia and corneal erosions.

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23
Q

What complications can arise from Hydroa Vacciniforme?

A

Scarring, embarrassment among children, and potential development of HV-like lymphoma in severe cases.

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24
Q

What role does Epstein-Barr virus (EBV) play in Hydroa Vacciniforme?

A

EBV may play a role in the pathogenesis of HV, with EBV nucleic acids found in 85% to 95% of HV lesions.

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25
Q

How does sunlight exposure affect Hydroa Vacciniforme?

A

Sunlight exposure leads to the eruption of lesions within 24 hours, with a symmetrical distribution on the face and hands.

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26
Q

What is the typical demographic affected by Hydroa Vacciniforme?

A

Patients with light pigmentation are affected preferentially, and it is rare with an incidence of 0.34 cases per 100,000 individuals.

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27
Q

What laboratory tests are used to support the diagnosis of Hydroa Vacciniforme (HV)?

A

Laboratory tests include blood, urine, and stool porphyrin to exclude cutaneous porphyria; ANA & ENA to exclude cutaneous lupus erythematosus; evidence of EBV viremia may support the diagnosis or indicate disease activity.

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28
Q

What are the early histologic changes observed in Hydroa Vacciniforme (HV)?

A

Early histologic changes include intraepidermal vesicle formation with spongiosis, focal epidermal keratinocyte necrosis, and dermal perivascular neutrophil and lymphocyte infiltrate.

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29
Q

What is the differential diagnosis for Hydroa Vacciniforme (HV)?

A

The differential diagnosis includes photoexacerbated viral dermatoses, erythropoietic protoporphyria, polymorphic light eruption, actinic prurigo, subacute cutaneous lupus, xeroderma pigmentosum, and Hydroa vacciniforme-like lymphoma (HVLL).

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30
Q

What management options are available for Hydroa Vacciniforme (HV)?

A

Management options include medications such as antiviral therapy with acyclovir and valacyclovir, dietary fish oil, prophylactic phototherapy, and counseling on strict sun protection.

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31
Q

What is the clinical course and prognosis for Hydroa Vacciniforme?

A

The clinical course often resolves in adolescence but may persist into adult life. Males tend to have later onset and longer duration.

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32
Q

What is the significance of EBV DNA levels in patients with Hydroa Vacciniforme?

A

Higher levels correlate with disease activity and severity.

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33
Q

What characterizes Hydroa Vacciniforme initially after sun exposure?

A

It is characterized initially by erythema, sometimes with swelling, followed by the eruption of tender papules and vesicles within hours of sun exposure.

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34
Q

What are the permanent scars left by lesions in HV called?

A

Permanent, depressed, hypopigmented scars, also called atrophic scars.

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35
Q

What is Chronic Actinic Dermatitis (CAD) and its common features?

A

Chronic Actinic Dermatitis (CAD) is a rare, acquired, persistent eczematous eruption of exposed skin, often with pseudolymphomatous features.

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36
Q

What are the commonly implicated allergens in Chronic Actinic Dermatitis?

A

Commonly implicated allergens include sesquiterpene lactones from the Compositae family and various chemical components in sunscreens.

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37
Q

What is the significance of photopatch testing in diagnosing Chronic Actinic Dermatitis?

A

Photopatch testing helps determine the safe dose of UVA for testing, whether there is a photoallergy present, and identifies relevant allergens.

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38
Q

How does Chronic Actinic Dermatitis differ in its presentation among various skin types?

A

It is more common in individuals with darker skin phototypes but can occur in all skin types.

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39
Q

What are the clinical features and history associated with Chronic Actinic Dermatitis?

A

Development in apparently normal skin or in skin with previous eczema, often affecting middle-aged and elderly men.

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40
Q

What is the presumed pathogenesis of CAD in a patient with a history of atopic eczema?

A

CAD may result from an allergic reaction to UVR-altered DNA or associated molecules.

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41
Q

What allergens should be considered in a patient with Chronic Actinic Dermatitis who has a history of using sunscreens?

A

Sunscreens are commonly implicated allergens.

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42
Q

What allergens should be tested in a patient with Chronic Actinic Dermatitis who has a history of airborne contact dermatitis?

A

Allergens such as sesquiterpene lactones from Compositae plants and methylisothiazolinone should be tested.

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43
Q

What is the relationship between Chronic Actinic Dermatitis and allergic contact dermatitis?

A

Patients with CAD often have concomitant allergic contact dermatitis to airborne and other ubiquitous allergens.

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44
Q

What factors may influence the prevalence of allergens in different regions for CAD?

A

Relevant allergens will differ in different parts of the world.

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45
Q

What is the role of UVR in Chronic Actinic Dermatitis?

A

Chronic photodamage from UVR may impair normal skin immunosuppression.

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46
Q

What is the clinical feature of the eruption in CAD?

A

The eruption is eczematous, requiring lower doses of UVR to evoke CAD than to produce erythema.

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47
Q

What demographic is classically affected by Chronic Actinic Dermatitis?

A

Middle-aged and elderly men.

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48
Q

What are the common characteristics of cutaneous lesions in Chronic Actinic Dermatitis (CAD)?

A

Eczematous, patchy, or confluent lesions that can be acute, subacute, or chronic.

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49
Q

What are the common characteristics of cutaneous lesions in Chronic Actinic Dermatitis (CAD)?

A
  • Eczematous, patchy, or confluent lesions
  • Can be acute, subacute, or chronic
  • Severe cases may show lichenification
  • Commonly affects habitually exposed areas with sharp cutoff at clothing lines
  • May present with pseudolymphomatous papules or plaques
  • Sparing of deep skin creases, upper eyelids, and finger webs
  • Irregular hyperpigmentation and hypopigmentation, sometimes vitiligo-like.
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50
Q

What laboratory tests are important for diagnosing Chronic Actinic Dermatitis (CAD)?

A
  • Histology: Look for epidermal spongiosis, acanthosis, and perivascular lymphocytic infiltrate.
  • Blood Tests:
    • Lupus autoantibodies to exclude cutaneous lupus erythematosus.
    • Circulating CD8+ Sézary cells in severe or erythrodermic CAD.
    • Assess HIV status if suspected as a predisposing factor.
    • Elevated Serum IgE levels correlate with more severe disease.
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51
Q

What is the significance of phototesting in the diagnosis of Chronic Actinic Dermatitis (CAD)?

A
  • Phototesting is essential for diagnosing CAD as it assesses erythemal thresholds and responses to UVB and UVA.
  • It helps identify drug reactions if only UVA sensitivity is present.
  • Testing should be performed on uninvolved skin without prior topical or systemic steroid therapy to avoid false negatives.
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52
Q

What are the potential complications associated with Chronic Actinic Dermatitis (CAD)?

A
  • Chronic Actinic Dermatitis (CAD) may coexist with cutaneous T-cell lymphoma (CTCL), but this is not expected by chance.
  • CTCL can rarely present with severe CAD-like photosensitivity, necessitating careful investigation to exclude CTCL when suspected.
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53
Q

A middle-aged man presents with eczematous lesions on sun-exposed areas that worsen in summer. What is the most likely diagnosis?

A

Chronic Actinic Dermatitis (CAD), which commonly affects middle-aged and elderly men and worsens in summer.

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54
Q

A patient with suspected Chronic Actinic Dermatitis (CAD) undergoes phototesting. What findings would confirm the diagnosis?

A

Phototesting shows decreased erythemal thresholds and eczematous or pseudolymphomatous responses after UVB, UVA, or visible light irradiation.

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55
Q

A patient with suspected photoallergy has a history of using sunscreens. What secondary complication should be considered?

A

Secondary contact or photocontact sensitivity to sunscreens may complicate the clinical picture.

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56
Q

A patient with suspected photoallergy has a history of using methylisothiazolinone. What is the relevance of this allergen?

A

Methylisothiazolinone is an airborne allergen that can be photoaggravated, resembling CAD.

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57
Q

A patient with suspected photoallergy has a history of using window glass for sunlight exposure. What is the relevance of this method?

A

Window glass filters out UVB, enabling testing with whole-spectrum sunlight minus UVB.

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58
Q

A patient with suspected photoallergy has a history of using a slide projector. What is the purpose of this device?

A

A slide projector is used for phototesting with visible light.

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59
Q

What is the typical presentation of cutaneous lesions in CAD?

A

Eczematous, patchy or confluent, and can be acute, subacute, or chronic.

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60
Q

What are common histological findings in CAD?

A

Epidermal spongiosis and acanthosis, with a predominantly perivascular lymphocytic cellular infiltrate confined to the upper dermis.

61
Q

What blood tests are important in diagnosing CAD?

A

Lupus autoantibodies, circulating CD8+ Sézary cells, and Serum IgE levels.

62
Q

What is the significance of phototesting in CAD diagnosis?

A

It is essential to confirm the diagnosis by assessing erythemal thresholds and responses to UVB and UVA.

63
Q

What are the complications associated with CAD?

A

CTCL and CAD may not coexist more than expected by chance, but CTCL can present with severe CAD-like photosensitivity.

64
Q

What factors can exacerbate CAD symptoms?

A

Sunlight exposure, particularly in summer, and the wavelengths of sensitivity extending to longer UVA or visible wavelengths.

65
Q

What is the role of patch and photopatch testing in CAD?

A

It helps identify contact sensitivity that may resemble or coexist with CAD.

66
Q

What are the features that may mimic cutaneous T-cell lymphoma (CTCL) in CAD?

A

Epidermal Pautrier-like microabscesses and deep, dense epidermotropic mononuclear cell infiltration.

67
Q

What are the predictors of poorer prognosis in Chronic Actinic Dermatitis (CAD)?

A

The predictors of poorer prognosis in CAD include:

  1. Severe phototest sensitivity
  2. A number of completely separate contact allergens
  3. Young age
  4. Female sex
68
Q

What are the main treatment options for refractory Chronic Actinic Dermatitis (CAD)?

A

The main treatment options for refractory CAD include:

  1. Azathioprine: 1.5 to 2.5 mg/kg/day can produce remission in months.
  2. Methotrexate: Especially effective when CAD has arisen on a background of atopic eczema.
  3. Cyclosporine: 3.5 to 5 mg/kg/day, rapidly effective but more likely to produce adverse effects.
  4. Mycophenolate mofetil: Less often used.
  5. Localized skin immunosuppression by psoralen activated by UVA treatment, often accompanied by oral and topical corticosteroid therapy to reduce disease flares.
69
Q

What preventive measures should be taken to avoid exacerbation of Chronic Actinic Dermatitis (CAD)?

A

Preventive measures for CAD include:

  • Moderating outdoor pursuits, especially those associated with plant allergen exposure, such as gardening.
  • Avoidance of UVR: Be aware that indoor lighting with fluorescent lamps, including compact fluorescent energy-saving lamps, is also a source of UVA and UVB.
70
Q

How does photoexacerbation affect dermatoses that are not caused by UVR?

A

Photoexacerbation can worsen several dermatoses that are not caused by UVR, leading to:

  • The initial condition becoming severely worsened, even if it was originally mild or subclinical.
  • Eczemas, psoriasis, and acne generally improving with sunlight exposure in most patients, but in a small proportion, it may be aggravated.
  • New eruptions developing or worsening initially at sites typical of the basic disorder, sometimes extending to other areas.
71
Q

A patient with Chronic Actinic Dermatitis (CAD) has severe phototest sensitivity and multiple contact allergens. What is the prognosis?

A

Severe phototest sensitivity and multiple contact allergens are predictors of poorer prognosis in CAD.

72
Q

A patient with Chronic Actinic Dermatitis (CAD) is treated with clobetasol propionate 0.05%. What is the expected outcome?

A

Clobetasol propionate 0.05% produces marked symptomatic relief without adverse effects if confined to affected skin.

73
Q

A patient with Chronic Actinic Dermatitis (CAD) has a history of using fluorescent lamps. What precaution should be taken?

A

Avoidance of UVR from fluorescent lamps, which emit UVA and UVB, is critical for patients with CAD.

74
Q

A patient with Chronic Actinic Dermatitis (CAD) has a history of using azathioprine. What is the recommended dosage for treatment?

A

Azathioprine is used at 1.5 to 2.5 mg/kg/day for refractory CAD.

75
Q

A patient with Chronic Actinic Dermatitis (CAD) has a history of using psoralen and UVA treatment. What is the expected outcome?

A

Psoralen activated by UVA treatment can be effective for localized skin immunosuppression in CAD.

76
Q

What are the predictors of poorer prognosis in Chronic Actinic Dermatitis (CAD)?

A

Severe phototest sensitivity, a number of completely separate contact allergens, young age, and female sex.

77
Q

What is the recommended treatment for disease flares in Chronic Actinic Dermatitis?

A

Oral steroids are recommended for disease flares.

78
Q

What is the role of topical corticosteroids in the treatment of Chronic Actinic Dermatitis?

A

Strong topical corticosteroids (clobetasol propionate 0.05%) can produce marked symptomatic relief without adverse effects, even after long-term use, if confined to affected skin.

79
Q

What preventive measures should be taken for individuals with Chronic Actinic Dermatitis?

A

Moderating outdoor pursuits, especially those associated with plant allergen exposure, and avoiding UVR is critical.

80
Q

What is photoexacerbation in the context of dermatological conditions?

A

Photoexacerbation refers to the worsening of several dermatoses that are not caused by UVR when exposed to it.

81
Q

What treatments are suggested for photoexacerbated seborrheic eczema?

A

Minimizing sunlight exposure, protection with suitable clothing, application of high-protection-factor broad-spectrum sunscreens, and careful treatment of the underlying disorder.

82
Q

What is the significance of avoiding UVR for individuals developing Chronic Actinic Dermatitis?

A

Avoidance of UVR is critical as it can exacerbate the condition, and indoor lighting with fluorescent lamps can also be a source of UVA and UVB.

83
Q

What oral immunosuppressive therapy is used for refractory Chronic Actinic Dermatitis?

A

Azathioprine, Methotrexate, and Cyclosporine are used for refractory CAD.

84
Q

What is the effect of sunlight exposure on conditions like eczema, psoriasis, and acne?

A

These conditions generally improve with sunlight exposure in most patients, but in a small proportion, it may be aggravated.

85
Q

What is the role of phototherapy in treating seborrheic or atopic eczema?

A

Phototherapy often helps in seborrheic or atopic eczema when other actions are inadequate, but it is contraindicated in cutaneous lupus erythematosus or dermatomyositis due to the risk of aggravating systemic disease.

86
Q

What are the three ways abnormal photosensitivity can present in patients?

A
  1. Sporadic: Patient usually considers sunlight exposure to be responsible.
  2. Persistent eruptions: Occur in sunlight-exposed areas, requiring physician identification of the association.
  3. Erythroderma: Generalized redness of the skin.
87
Q

What factors are considered important in the clinical presentation of photosensitivity disorders?

A
  • Age at disease onset
  • Gender: Different conditions affect different genders (e.g., PLE/PMLE in young women, AP in women or girls).
  • Family history: FHx of sunlight sensitivity may be present.
  • Previous sunlight sensitivity
  • Occupation and leisure pursuits: Common in outdoor enthusiasts.
  • Systemic and topical drug use.
88
Q

What are the characteristics of lesions in PLE/PMLE?

A

Lesions in PLE/PMLE can be:
- Small or large
- Elevated, pruritic, red or skin-colored
- Often clumped spots of papules, sometimes confluent
- Usually involve several, but not all exposed sites.

89
Q

What laboratory studies are recommended for diagnosing photosensitivity disorders?

A
  1. ANA & ENA: If significant titers, consider cutaneous lupus erythematosus.
  2. Blood, urine, and stool exams: For porphyrins.
  3. Biopsies: Helpful but rarely entirely diagnostic.
  4. Phototesting: To confirm conditions like XP and assess skin reactions.
  5. Patch & Photopatch testing: To identify relevant allergens.
  6. Assessment of DNA excision repair: Essential for diagnosing certain genophotodermatoses.
90
Q

What is the significance of phototesting in the diagnosis of photodermatoses?

A

Phototesting is the investigational technique of choice for photodermatoses, which includes:
- Monochromator phototesting: Tests to wavebands, not strictly monochromatic, to identify skin reactions at specific doses.
- Helps confirm conditions like XP by assessing delayed erythema development and identifying action spectrum.

91
Q

What are the three ways abnormal photosensitivity can present in patients?

A

Sporadic, persistent eruptions in sunlight-exposed areas, and erythroderma.

92
Q

Which gender is most commonly affected by PLE/PMLE?

A

Young women.

93
Q

What is a common symptom of solar urticaria?

A

Elevated pruritic wheals that are often confluent.

94
Q

What is the significance of family history in photosensitivity disorders?

A

A family history of sunlight sensitivity may be present in patients with PMLE/PLE, AP, XP, and the porphyrias.

95
Q

What laboratory studies are recommended for suspected photodermatoses?

A

ANA & ENA, blood, urine, and stool exams for porphyrins, and biopsies may be helpful.

96
Q

What is the purpose of phototesting in the diagnosis of photodermatoses?

A

To identify the action spectrum and confirm conditions like XP by assessing delayed erythema development.

97
Q

What type of skin reaction is associated with Erythropoietic Porphyria?

A

Firm, colorless or pink, diffuse swelling after lengthy exposure.

98
Q

What is a common characteristic of photosensitivity eruptions?

A

They are usually present on sun-exposed areas such as the forehead, nose, and upper cheeks.

99
Q

What is the typical onset time for PLE/PMLE after sun exposure?

A

Onset within 20 minutes to several hours, with resolution over days after exposure ceases.

100
Q

What is the investigational technique of choice for photodermatoses?

A

Phototesting.

101
Q

What is the purpose of photoprovocation with a broad-spectrum source in the context of actinic prurigo?

A

Photoprovocation with a broad-spectrum source is used to induce the eruption for its clinical appearance and subsequent biopsy if indicated. A solar simulator, which is a xenon arc-filtered device, is favored as it produces a spectrum resembling the terrestrial sunlight spectrum at noon on a cloudless midsummer’s day.

102
Q

What are the main components of a monochromator used in phototesting?

A

A monochromator is composed of a high-pressure xenon arc source that emits radiation along a pathway incorporating a diffraction grating angled to produce the required waveband at the exit slit. It is preferably performed on unaffected skin of the upper back, lateral to the paravertebral groove.

103
Q

What precautions should be taken before phototesting to prevent false-negative results?

A

To prevent false-negative results, it is advised to avoid the use of potent topical and systemic steroids for at least several days before phototesting. Additionally, other oral immunosuppressive agents should be stopped whenever possible.

104
Q

What is the significance of confirmatory photoallergy in photopatch testing?

A

Confirmatory photoallergy is indicated by strongly positive reactions at sites exposed to both the chemical agent and UVA, with no reactions at the covered control sites. This helps in diagnosing photoallergy accurately.

105
Q

What are the potential risks associated with phototesting?

A

Phototesting can be potentially harmful to both skin and eyes; therefore, patients and investigators should be protected with appropriate clothing, shielding, and goggles during the procedure.

106
Q

A patient with Chronic Actinic Dermatitis (CAD) has lesions on the upper back. What is the preferred site for phototesting?

A

Phototesting is preferably performed on unaffected skin of the upper back, lateral to the paravertebral groove.

107
Q

A patient with Chronic Actinic Dermatitis (CAD) has a history of using methotrexate. How might this affect phototesting?

A

Methotrexate can affect phototesting results, and its use should be stopped whenever possible before testing.

108
Q

A patient with suspected photoallergy undergoes photopatch testing. What finding confirms photoallergy?

A

Strongly positive reactions at sites exposed to both the chemical agent and UVA, with no reactions at covered control sites, confirm photoallergy.

109
Q

A patient with suspected photoallergy has widespread positive reactions in photopatch testing. What does this indicate?

A

Widespread positive reactions may indicate underlying UVA photosensitivity rather than true photoallergy.

110
Q

A patient with suspected photoallergy has a history of using PUVA therapy. What is the typical UVA dose used in photopatch testing?

A

A broad-spectrum UVA source, usually at 5 J/cm², is used in photopatch testing.

111
Q

What confirms photoallergy in photopatch testing?

A

Strongly positive reactions at sites exposed to both the chemical agent and UVA confirm photoallergy.

112
Q

What do widespread positive reactions in photopatch testing indicate?

A

Widespread positive reactions may indicate underlying UVA photosensitivity rather than true photoallergy.

113
Q

What is the typical UVA dose used in photopatch testing?

A

A broad-spectrum UVA source, usually at 5 J/cm², is used in photopatch testing.

114
Q

What is the purpose of fluorescent UVA lamps in testing?

A

Fluorescent UVA lamps are used to irradiate test sites in photopatch testing to identify photoallergic contact dermatitis.

115
Q

What is the purpose of a solar simulator in phototesting?

A

A solar simulator is used to induce eruptions for clinical appearance and subsequent biopsy.

116
Q

What is the purpose of a xenon arc irradiation monochromator?

A

A xenon arc irradiation monochromator is used for precise characterization of wavelength dependency in phototesting.

117
Q

What is the purpose of a diffraction grating in phototesting?

A

A diffraction grating in a monochromator produces the required waveband at the exit slit for phototesting.

118
Q

What is the purpose of using a geometric series of doses in phototesting?

A

A geometric series of doses is used in phototesting to standardize sequential doses and wavelengths.

119
Q

What is the purpose of protective goggles during phototesting?

A

Protective goggles are used to prevent harm to the eyes during phototesting.

120
Q

What is the purpose of shielding during phototesting?

A

Shielding is used to protect the patient and investigator from harmful radiation during phototesting.

121
Q

What is the purpose of a reduced-light environment in phototesting?

A

A reduced-light environment is used to control eruptions and prevent false-positive results in phototesting.

122
Q

What is the relevance of azathioprine in phototesting?

A

Azathioprine can affect phototesting results, and its use should be stopped whenever possible before testing.

123
Q

What is the relevance of methotrexate in phototesting?

A

Methotrexate can affect phototesting results, and its use should be stopped whenever possible before testing.

124
Q

What is the purpose of photopatch testing?

A

To identify photoallergic contact dermatitis and phototoxic agents.

125
Q

What device is favored for photoprovocation in phototesting?

A

A solar simulator, usually a xenon arc-filtered source.

126
Q

What should be avoided before phototesting to prevent false-negative results?

A

Use of potent topical and systemic steroids.

127
Q

What is the mainstay of phototesting?

A

Monochromator, composed of a high-pressure xenon arc source.

128
Q

What is a potential risk associated with phototesting?

A

It can be potentially harmful to both skin and eyes.

129
Q

What is the recommended procedure for applying test materials in photopatch testing?

A

Test materials are applied in duplicate for 24 to 48 hours to normal skin.

130
Q

What is the significance of confirming photoallergy in photopatch testing?

A

Strongly positive reactions at sites exposed to both chemical agent and UVA indicate photoallergy.

131
Q

What should be done to determine the minimal erythemal dose before photopatch testing?

A

Irradiations with the planned UVA source should be conducted.

132
Q

What can cause false-positive results in phototesting?

A

Widespread disease or photoaggravation of an underlying process.

133
Q

What are the commonly implicated allergens in Chronic Actinic Dermatitis (CAD)?

A

Commonly implicated allergens in CAD include fragrance and sunlight.

134
Q

What test is essential to diagnose Chronic Actinic Dermatitis (CAD)?

A

The essential test to diagnose CAD is photopatch testing.

135
Q

What are the predictors of poorer prognosis in Chronic Actinic Dermatitis (CAD)?

A

Predictors of poorer prognosis in CAD include age of onset, duration of disease, presence of other skin conditions, and history of significant sun exposure.

136
Q

What treatment in Chronic Actinic Dermatitis (CAD) produces marked symptomatic relief without adverse effects?

A

The treatment that produces marked symptomatic relief without adverse effects, even after long-term use, if confined to affected skin is topical corticosteroids.

137
Q

What condition presents as an exaggerated sunburn-like reaction, maximal at 2-3 days?

A

The condition that presents as an exaggerated sunburn-like reaction, maximal at 2-3 days is photoallergy.

138
Q

What is the mainstay of phototesting in Chronic Actinic Dermatitis (CAD)?

A

The mainstay of phototesting is photopatch testing.

139
Q

Where is the site preferably performed for phototesting in Chronic Actinic Dermatitis (CAD)?

A

The site where phototesting is preferably performed is the upper back.

140
Q

What finding in photopatch testing is confirmatory of photoallergy?

A

The finding in photopatch testing that is confirmatory of photoallergy is positive reaction to specific allergens upon UV exposure.

141
Q

What are commonly implicated allergens in Chronic Actinic Dermatitis (CAD)?

A

Two allergens are typically identified.

142
Q

What test is essential for diagnosing Chronic Actinic Dermatitis (CAD)?

A

A specific diagnostic test is required.

143
Q

What are predictors of poorer prognosis in Chronic Actinic Dermatitis (CAD)?

A

Several factors can indicate a worse prognosis.

144
Q

What treatment in Chronic Actinic Dermatitis (CAD) provides symptomatic relief without adverse effects?

A

A topical treatment confined to affected skin is effective.

145
Q

What condition presents as an exaggerated sunburn-like reaction, peaking at 2-3 days?

A

This describes a specific photodermatitis condition.

146
Q

Where is the mainstay of phototesting preferably performed?

A

A specific site is recommended for phototesting.

147
Q

What finding in photopatch testing confirms photoallergy?

A

A specific result indicates photoallergy.

148
Q

What is the mainstay of phototesting?

A

A standard procedure is used for phototesting.

Fitzpatrick's Dermatology, 9th Edition (Chapter-based Decks) (48 decks)

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