17 - 95 - ACTINIC DERMATITIS Flashcards
rare, acquired, persistent eczematous eruption of exposed skin, sometimes having pseudolymphomatous (reticuloid) features
CHRONIC ACTINIC DERMATITIS
The lesions of CAD are eczematous, patchy or confluent, and acute, subacute, or chronic (Figs. 95-1 and 95-2).
what areas are usually spared in chronic actinic dermatitis?
There is sparing of deep skin creases, upper eyelids, finger webs, and skin behind the earlobes
Several dermatoses that are not caused by UVR may be worsened by it. Mechanisms of this phenomenon is called ______
photoexacerbation
Diseases Sometimes Exacerbated by Ultraviolet Irradiation
Patients with abnormal photosensitivity present in 3 ways:
(a) sporadic or (b) persistent eruptions in sunlight-exposed areas (Fig. 95-4), or, infrequently, (c) erythroderma.
An eruption appearing in minutes and remitting within 2 hours suggests ______
solar urticaria or, occasionally, photosensitivity to drugs, such as amiodarone
Onset within 20 minutes to several hours, with resolution over days suggests ________
PLE/PMLE, HV, erythropoietic protoporphyria, cutaneous lupus erythematosus, or other photoexacerbated dermatoses, or other drug photosensitivities, such as to thiazides
Phototesting falls into 2 categories:
(a) monochromator phototesting (testing to wavebands, it is not strictly monochromatic, produced by an irradiation monochromator), usually of the upper back with selected wavebands and selected doses to identify the action spectrum for the disorder and to provoke the eruption (frequently responses at 24 hours and later after irradiating small circles of back skin with a monochromator look eczematous in CAD), and
(b) photoprovocation with a broad-spectrum source to induce the eruption for its clinical appearance and subsequent biopsy if indicated
Edilberto is a 75 year old male retired gardener who came in to your clinic with a chief complaint of pruritic plaques on the neck and forearms with sparing of deep skin creases. With the diagnosis in mind, which one is a close differential?
a. Cutaneous T-Cell Lymphoma
b. Polymorphic light eruption
c. Hydroa Vacciniforme
d. Solar urticaria
A
Edilberto is a 75 year old male retired gardener who came in to your clinic with a chief complaint of pruritic plaques on the neck and forearms with sparing of deep skin creases.
Which is TRUE about Edilberto’s case?
a. It usually involves severe sensitivity to UVA
b. It affects older men, women and children
c. It is likely the result of a Type 1 hypersensitivity reaction against an endogenous photoinduced antigen
d. All of the above are true
B
Edilberto is a 75 year old male retired gardener who came in to your clinic with a chief complaint of pruritic plaques on the neck and forearms with sparing of deep skin creases.
Which is FALSE regarding Edilberto’s case?
a. Once established, this usually persists for years before resolving gradually.
b. Phototesting is essential to make the diagnosis in his case
c. Phototesting should be done on the involved skin on the arms with no topical or oral steroid medications prior to testing
d. Assessment of lupus antibodies is usually done to exclude cutaneous lupus erythematosus
C
Edilberto is a 75 year old male retired gardener who came in to your clinic with a chief complaint of pruritic plaques on the neck and forearms with sparing of deep skin creases.
What blood tests can you ask Edilberto to do to rule out other possible causes?
a. Serum Immunoglobulin E
b. HIV testing
c. Lupus autoantibodies
d. All of the above
D
investigational technique of choice for photodermatoses when the diagnosis is uncertain or when details of the inducting action spectrum are required
PHOTOTESTING
mainstay of phototesting
monochromator
- 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
- Monochromator phototesting is preferably performed on unaffected skin of the upper back, lateral to the paravertebral groove whereas lesion induction, except when done relatively easily with the monochromator, as in solar urticaria and CAD, is best undertaken using broadband sources with output directed over larger areas of skin known to be susceptible to the eruption.
conditions in which repeated irradiation with UVAemitting or UVB-emitting or combined sources is often required to reproduce the disease
PLE/PMLE, actinic prurigo, and HV
an established investigational tool designed to identify photoallergic contact dermatitis, although it also can be employed to help identify phototoxic agents
photoallergic contact dermatitis
