Title: GZ / The Grenz Zone Season 1 / Ep 8
Tags: GZ DermnetNZ

Parapsoriasis is broken down into small plaque parapsoriasis, in which scaly patches < 5 cm in diameter and does not have association with cutaneous lymphomas, and large plaque parapsoriasis, which presents with scaly patches > 5 cm in diameter and has an association with mycosis fungoides
Back Extra: 10-35% of LPP cases will progress to MF in 6-10 years

Q: Parapsoriasis is made up of [patches/plaques]
A: patches
Back Extra: The terms small and large plaque parasporiasis are misnomers

Q: Parapsoriasis often presents in patients 40's and affects [...] more than [...] in a 3:1 distribution
A: males; females

Q: What areas are commonly affected by parapsoriasis?
[...]
A: Sun-protected areas (ie bathing suit distribution)
Back Extra: Similar to mycosis fungoides

Q: [...] is a variant of [...] plaque parasporiasis and presents with long finger-like patches along cleavage lines on the flanks
A: Digitate dermatosis; small
Back Extra: While patches may be longer than 5 cm in digitate dermatosis, it is still considered a variant of SPP because of its very low risk of progression to cutaneous lymphomas

Q: [...] is a variant of [...] plaque parasporiasis characterized by wide-spread erythematous scaly
patches in a net-like distribution.
Almost all cases progress to mycosis fungoides
A: Retiform parapsoriasis; large

Q: On histology of parapsoriasis, mild lymphocytic infiltrate may be seen at the DEJ predominantly made of CD - [...]+ T cells and may have T-cell clonality, especially in large plaque parasporiasis
A: 4
Back Extra: In addition, both SPP and LPP have parakeratosis, corresponds to the scale seen clinically, and mild acanthosis and spongiosis

Q: Two unique findings (grossly) of the plaques seen in pityriasis rubra pilaris
[...]
[...]
A: Salmon to red orange color; Islands of sparing

Q: [...] may begin with scalp erythema with scale, red/brown follicular papules with central keratotic plug having a “[...]” appearance affecting the neck, head, trunk, extensor extremities, and dorsal fingers, which eventually coalesce to scaly plaques w/ a salmon to red orange color
A: Pityriasis rubra pilaris; nutmeg grater
Back Extra: These plaques are generally diffuse and symmetric with islands of sparing (patches of normal skin within affected areas)
Look for keratoderma (“PRP sandals”: thick hyperkeratosis of the skin of palms and soles
Thickened yellow brittle nails, NO PITTING (vs. pitting seen in psoriasis)

Q: Patients with pityriasis rubra pilaris may present with [...], which refers to a thick hyperkeratosis of the skin of palms and soles (“PRP sandals”) and [nail findings]
A: keratoderma; thickened yellow brittle nails
Back Extra: NO PITTING (vs. pitting seen in psoriasis)

Name the six types of pityriasis rubra pilaris
Type 1) Classical Adult (55%): Rapid onset of clinical findings w/ good clinical prognosis. 80% cases resolving over 3 years
Type 2) Atypical Adult (5%): Chronic course of ichthyotic leg lesions, keratoderma, alopecia
Type 3) Classical Juvenile (10%): Same clinical picture of type 1 but presenting in patients < 2 y/o
Type 4) Localized/Circumscribed Juvenile (25%) Symmetric keratotic follicular papules and erythematous plaques on extensor fingers, elbows, and knee. Most common type of PRP in children
Type 5) Atypical Juvenile (5%): Chronic follicular hyperkeratosis and erythema + scleroderma-like
tightening of hands and feet
Type 6) HIV associated PRP (1%): Associated follicular spines, acne conglobata, hidradenitis suppurativa
Back Extra: Type 5 is most likely to have a genetic component
Circumscribed juvenile shown

Biopsy findings (histology) of pityriasis rubra pilaris
“Checkerboard” pattern: alternating orthokeratosis and parakeratosis w/ hyper and hypogranulosis
Irregular acanthosis
Follicular plugging
Shoulder parakeratosis
Back Extra: Looks like a “checkerboard” because you have orthokeratosis (without nuclei) sitting above purple hypergranulosis alternating with parakeratosis (has purple nuclei) sitting above hypogranulosis
Shoulder parakeratosis - Parakeratosis tends to be present at the edges of the hair follicle orifice

Q: Systemic [...] are often used first line in the treatment of pityriasis rubra pilaris, as it may clear PRP in 6 months
A: retinoids
Back Extra: Acitretin or isotretinoin (1mg/kg per day) are often used
In addition, methotrexate, TNF-alpha inhibitors, cyclosporine, azathioprine, and phototherapy have also been used successfully
Steroids are not that helpful, which makes sense since there aren't many inflammatory cells seen on hisotology