23: Nummular Eczema, Lichen Simplex Chronicus, Prurigo Nodularis Flashcards
What are the common clinical findings associated with nummular eczema?
Well-demarcated, coin-shaped plaques (1 to >3cm in size), formed from coalescing papules and papulovesicles, often studded with satellite papulovesicles at the periphery. Pinpoint oozing and crusting may occur. Chronic plaques are dry, scaly, and lichenified, with a classic distribution on the extensor aspects of the extremities, particularly the lower extremities.
What factors are associated with the etiology and pathogenesis of nummular eczema?
Multifactorial pathogenesis with overlap with triggers of atopic dermatitis such as atopy, xerosis, and irritants. Not consistently associated with atopy; low rates of personal and family history of atopy. In elderly patients, associated with xerosis and lower hydration of the stratum corneum. Predominantly T cell inflammation, commonly flares in winter, triggered by irritants and environmental allergens.
What complications can arise from nummular eczema?
Profound sleep disturbance due to intense itch and secondary bacterial infection.
What is the prognosis and clinical course of nummular eczema?
Considerable quality-of-life impairment, often chronic with intermittent or persistent courses. Lesions may recur at prior sites of involvement, with some cases persisting for up to 30 years and a mean duration of 3.8 years; only 44% of patients may ever be free of lesions.
Can topical medicaments cause nummular dermatitis?
Yes. The patient might develop NE-like reactions characterized by coin-shaped plaques with pinpoint oozing and crusting.
How might a history of dental abscesses relate to a patient with Nummular Eczema?
Nummular Eczema has been associated with higher rates of dental abscesses and paradental diseases.
What does it indicate if a patient with Nummular Eczema has lesions not associated with elevated serum IgE levels?
This indicates that Nummular Eczema is not consistently associated with atopy.
Can Nummular Eczema recur at prior sites?
Yes. Nummular Eczema often has a chronic course with recurrence at prior sites.
What stage of Nummular Eczema do dry, scaly, and lichenified lesions represent?
This represents the chronic stage of Nummular Eczema.
What laboratory test might be useful for chronic and recalcitrant cases of Nummular Eczema with sterile lesions?
Patch testing might be useful to rule out underlying allergic contact dermatitis.
What environmental and patient factors might contribute to flares of Nummular Eczema?
Environmental factors include winter season, exposure to irritants or allergens. Patient factors include xerosis and lower hydration of the stratum corneum.
What is the most likely diagnosis for a patient with coin-shaped plaques on lower extremities formed from coalescing papules?
The most likely diagnosis is Nummular Eczema. Common triggers include atopy, xerosis, irritants, allergens, microbial colonization, and emotional stress.
Should bacterial culture be considered for a patient with lesions of Nummular Eczema?
Bacterial culture should be considered only for suspected superimposed infection.
What are the common triggers for nummular eczema and how do they relate to atopy?
Common triggers include atopy, xerosis, irritants, allergens, and infection. However, nummular eczema does not consistently associate with atopy.
What are the hallmark clinical findings in patients with Lichen Simplex Chronicus and Prurigo Nodularis?
The hallmark clinical finding is severe itching.
What are the main treatment options for Lichen Simplex Chronicus and Prurigo Nodularis?
Main treatment options include superpotent topical corticosteroids, topical calcineurin inhibitors, emollients for xerosis, oral sedating antihistamines, oral antibiotics for secondary infections, and phototherapy for widespread lesions.
What psychological factors are associated with Lichen Simplex Chronicus and Prurigo Nodularis?
There is a bidirectional relationship; anxiety disorders increase the risk of LSC, and patients with LSC and Prurigo Nodularis often have higher rates of depression, anxiety, and OCD.
What are the typical characteristics of prurigo nodularis (PN)?
Typical characteristics include severe pruritus with nodules ranging from few to hundreds, firm to hard nodules measuring 0.5 cm to >3.0 cm, often hyperkeratotic or crateriform, with common sites on limbs, abdomen, and sacrum.
What laboratory tests may be requested for suspected systemic causes in patients with Lichen Simplex Chronicus?
Tests may include CBC with differential, renal, liver, and thyroid function tests, tests for HIV and diabetes, and additional tests for iron deficiency and other conditions.
What findings can a skin biopsy reveal in patients with Lichen Simplex Chronicus?
A biopsy can reveal hyperkeratosis, thickened collagen in the papillary dermis, and variable inflammatory infiltrate.
What is the most common site for Prurigo Nodularis nodules?
The most common site for Prurigo Nodularis nodules is the limbs, especially the extensor areas.
What histopathological findings are typical in Lichen Simplex Chronicus?
Histopathological findings include hyperkeratosis, parakeratosis, orthokeratosis, hypergranulosis, psoriasiform epidermal hyperplasia, and thickened collagen bundles in the papillary dermis.
What is the most common site for nodules in Prurigo Nodularis?
The most common site for Prurigo Nodularis nodules is the limbs, especially the extensor areas.
What additional diagnostic test might be needed for nodules with a crateriform surface in Prurigo Nodularis?
A skin biopsy may be needed to rule out primary pruritic disorders like psoriasis.
