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.
What is the typical size range of nodules in Prurigo Nodularis?
The size range of Prurigo Nodularis nodules is 0.5 cm to >3.0 cm.
What post-resolution changes might occur in Prurigo Nodularis?
Other changes include post-inflammatory hyperpigmentation or hypopigmentation.
What other signs of atopy might be present in Lichen Simplex Chronicus?
Other signs of atopy include Dennie-Morgan folds and palmar hyperlinearity.
What characteristic sign might be observed in Prurigo Nodularis on the upper back?
The ‘butterfly sign,’ which shows lesional sparing on the upper back, might be observed.
What are the most common sites for Lichen Simplex Chronicus?
The most common sites for Lichen Simplex Chronicus are the scalp, nape of the neck, ankles, extensor areas, and anogenital regions.
What potential outcomes might occur after resolution of Prurigo Nodularis nodules?
Potential outcomes include post-inflammatory hyperpigmentation, hypopigmentation, and scarring.
What related physical findings might be observed in a patient with a history of atopic dermatitis and Lichen Simplex Chronicus?
Related findings include lichenified and xerotic intervening skin, Dennie-Morgan folds, and palmar hyperlinearity.
What condition is indicated by lichenified, dry, and scaly plaques on the nape of the neck, and what is the primary cause?
The condition is Lichen Simplex Chronicus (LSC), primarily caused by repeated rubbing and scratching.
What is the diagnosis for firm nodules on limbs that are hyperkeratotic and excoriated?
The diagnosis is Prurigo Nodularis (PN). A characteristic sign is the ‘butterfly sign,’ which shows lesional sparing on the upper back.
What diagnostic imaging might be necessary for localized Lichen Simplex Chronicus?
A cervical spinal column MRI may be necessary to evaluate localized LSC or PN, especially in a brachioradial distribution.
What condition might severe itching triggered by sweating and psychological distress indicate?
This might indicate Lichen Simplex Chronicus (LSC). The hallmark symptoms include severe itching, burning, stinging, or a creepy-crawly sensation.
What secondary behavior might explain the distribution of nodules in hard-to-reach areas in Prurigo Nodularis?
The distribution may be due to the use of backscratchers, knives, forks, or brushes to scratch these areas.
What are the common triggers for pruritus in patients with Lichen Simplex Chronicus?
Common triggers for pruritus in patients with LSC include sweating, heat, friction, extreme humidity, dryness, irritation from personal care products or clothing, and psychological distress.
What are the characteristic cutaneous lesions associated with Prurigo Nodularis?
Characteristic cutaneous lesions associated with Prurigo Nodularis (PN) include firm to hard nodules, hyperkeratotic or crateriform surface, common sites on limbs, abdomen, and sacrum, butterfly sign, and persistence with post-inflammatory changes.
What laboratory tests may be requested for suspected systemic causes in patients with Lichen Simplex Chronicus?
Laboratory tests may include CBC with differential, renal, liver, and thyroid function tests, HIV and diabetes testing, iron deficiency testing, ESR, gliadin antibody, zinc, cobalamin, total porphyrins, stool examination for Strongyloides stercoralis, CXR for lymphoma, abdominal or LN ultrasound, and breath tests.
What findings might a skin biopsy reveal in a patient with Lichen Simplex Chronicus?
A skin biopsy may reveal hyperkeratosis with parakeratosis, orthokeratosis, hypergranulosis, psoriasiform epidermal hyperplasia, thickening of collagen in the papillary dermis, and variable inflammatory infiltrate.
What is the significance of PCR testing in Prurigo Nodularis?
PCR testing is used to check for mycobacteria if histopathological examination reveals granulomatous inflammatory infiltrate.
What are the common complications associated with Prurigo Nodularis?
Common complications include sleep cycle disturbances, depression, anxiety, OCD, higher rates of diabetes, hypertension, hyperlipidemia, cardiovascular disease, peripheral arterial disease, chronic kidney disease, and increased risk of erectile dysfunction.
How does the prognosis of Lichen Simplex Chronicus and Prurigo Nodularis differ in systemic disease?
In systemic disease, Lichen Simplex Chronicus (LSC) and Prurigo Nodularis (PN) tend to have a more prolonged course compared to cases without systemic involvement.
What treatment strategies are recommended for managing Prurigo Nodularis?
Treatment strategies include interrupting the itch-scratch cycle, identifying and addressing systemic causes, avoiding scratching, and utilizing occlusive measures.
What findings are associated with S100 staining in Prurigo Nodularis?
S100 staining may show cutaneous neural hypertrophy with thickened nerve bundles and an increase in nerve fibers.
What other comorbidities are commonly associated with Prurigo Nodularis?
Comorbidities include hyperlipidemia, cardiovascular disease, peripheral arterial disease, chronic kidney disease, depression, and anxiety.
What occlusive measures can be used for lesions refractory to conventional treatment in Lichen Simplex Chronicus?
Occlusive measures include plastic films, topical steroid-impregnated tape, or Unna boots.
What combination therapy has shown effectiveness in reducing itch in Prurigo Nodularis?
A combination of montelukast and fexofenadine has been effective in reducing itch in 75% of patients.
What are the key diagnostic tests for Prurigo Nodularis and their significance?
Key diagnostic tests include PCR for mycobacteria, epidermal and papillary dermal findings similar to LSC, and S100 staining indicating neural involvement.
What complications are associated with Prurigo Nodularis?
Complications include sleep cycle disturbances, psychological disorders, cardiovascular risks, and increased risk of erectile dysfunction.
How does the prognosis of Prurigo Nodularis differ in systemic disease compared to isolated cases?
In systemic disease, PN often has a chronic course with persistence or recurrence of lesions and increased exacerbations.
What treatment strategies are recommended for managing Prurigo Nodularis?
Recommended strategies include interrupting the itch-scratch cycle, identifying systemic causes, medications, avoiding scratching, and using occlusive measures.
