PRP Flashcards
What are the subtypes of PRP?
Type I (classic adult)
* most common form (55%)
* typically self-limited,
* clearing within 3 years in 80% of patients.
**Type II (atypical adult) **
* Less common (5%), also seen in adults
* differs from type I by a palmoplantar keratoderma with a coarse and lamellated scale, a more ichthyosiform scaling on the lower extremities, and occasional alopecia
* More of a chronic course
Types III–V are seen in children and adolescents.
Type III (classic juvenile)
* represents 10% of cases
* most closely resembles the classic adult form
* typically clears within 3 years.
**Type IV (juvenile circumscribed) **
* The most common of the juvenile forms
* focal nature sets it apart from the other clinical presentations
Type V (atypical juvenile)
* has features similar to adult type II disease with more ichthyosiform scaling and a chronic course.
Type VI (HIV associated)
* Overlap with type I
* associated with HIV
What are the biopsy findings of PRP?
Psoriasiform dermatitis
Irregular hyperkeratosis and **alternating vertical and horizontal orthokeratosis and parakeratosis **(‘checkerboard pattern’)
Hair follicles dilated and filled with a keratinous plug (follicular plugging) with the ‘shoulder’ of stratum corneum surrounding the follicular opening showing parakeratosis (shoulder parakeratosis)
Interfollicular epidermis has hypergranulosis (intact granular layer) and thick, shortened rete ridges
Sparse lymphohistiocytic perivascular infiltrate in underlying dermis
+/- spongiosis, acantholysis and focal acantholytic dyskeratosis within the epidermis (if present, helpful in distinguishing from psoriasis), eosinophils
What are the key features of Type I PRP?
Type I PRP = Classic adult
- accounts for 55% of cases of PRP
- Erythroderma
- Islands of sparing
- follicular hyperkeratosis
- waxy diffuse PPKD
- Cephalocaudal spread
80% remit within 3 years
Relapses are uncommon
What is type II PRP?
Type II PRP = II: Atypical adult
* Accounts for 5% of PRP diagnoses
* Generalised
* Areas of eczematous dermatitis with follicular hyperkeratosis
* Icthyosiform / ezcematous lesions of the legs
* Keratoderma with coarse lamellated scale
* Sparse scalp hair
Long duration >20 years
What is Type III PRP?
Type III PRP = Classic juvenile
- accounts for **10% **of PRP cases
- Generalised
- Peak onset first two years of life and in adolescence
- Same features as type I (adult)
Clears within 3 years
What is type 4 PRP?
Type 4 PRP = circumscribed juvenile PRP
- Accounts for 25% of PRP cases
- Pre-pubertal onset
- Localised to the elbows and knees, palms / soles
- follicular papules, erythema
- Resembles psoriasis
Long term outcome unclear, but possible improvement in late teens
What is type V PRP?
Type V PRP = Atypical juvenile
- Affects 5% of PRP cases
- Begins in first few years,
- accounts for most familial cases,
- follicular hyperkeratosis, scleroderma-like appearance of hands and feet,
- generalised
Chronic course / persistent, improvement with retinoids but relapses when stopped
frequently due to CARD14 mutations;
What is type VI PRP?
Type VI = HIV associated
- Accounts for <1 % of cases
- Overlap with type 1
- Ass with
Acne conglobata, folicular spines, HS
Label the arrows
What are the key histological features of PRP? (6)
Alternating parakeratosis with orthokeratosis = checkerboard pattern
Follicular Plugging
Shoulder Parakeratosis
Irregular acanthosis (often psorsiform)
Perivascular lympho-histiohitic infiltrate
Hypergranulosis
Rook and Rapini
Describe the key features
a)
* Hyperkeratosis with follicular plugging (keratin-plugged follicles)
* parakeratosis adjacent to both sides of the follicular ostium (‘shoulder parakeratosis’).
* scarce, superficial, dermal, perivascular lymphohistiocytic infiltrate and lack of neutrophils.
**(b) **
* Irregular psoriasiform acanthosis
* alternating ortho- and parakeratosis (‘checkerboard’ pattern)
Rook
What gene is ass with familial PRP?
CARD14
What is the subtype of PRP of (a) and (b)?
A - type III (juvenile - classic)
B - type IV (juvenile - circumscribed)
What are the nail findings in PRP?
Thickened nail plate,
Yellow-brown discoloration
Subungual hyperkeratotic debris
Normally an absence of pitting (seen in psoriasis)
What are the treatment options for PRP?
**General measures: **emollients, antihistamines, time off work (lethargy)
Topicals
- Medium to high potency topical corticosteroids
- Keratolytics (eg. 10% urea or 5% salicylic acid), tar, calcipotriol, topical tretinoin/tazarotene, calcineurin inhibitors
**First line: retinoids **
- 1mg/kg/day of isotretinoin or 0.5mg/kg/day of acitretin
- Response usually evident within 3-6 months
Second line: MTX
- 5-25mg/week
- Response usually evident in 3-6 months
- Can be used with systemic retinoids in difficult cases
- Monitor for hepatotoxicity (rare)
Other agents
Third Line
- TNF alpha inhibitors (adalimumab, infliximab, etanercept),
- ustekinumab (IL 12 / 23)
- IL-17 blockers (secuzinumab, izekinumab)
- IVIG
- AZA,
- CSA,
- prednisolone
- Phototherapy (UVB/PUVA/UVA-1, phototesting prior as some cases photoexacerbated) + retinoids
HIV associated: zidovudine, retinoids + zidovudine, triple antiviral therapy
What are the clinical features of PRP?
Classic presentation:
Hyperkeratotic papules - orange / salmon red
Perifollicular accentuation and sclae
- nutmeg grater appearance on the dorsal aspects of the hand
Coalesce into plaques and occ into erythroderma
Islands of sparing
Cephalocaudal spread
Wazy, orange - palmarplantar keratoderma
Subungal hyperkeratosis
Nail plate thickening
Splinter haemorrhages
Ectropion
Eclabian
Eruptive seb Ks
Rook and bolognia
What are the clinical signs?
Islands of sparing
Nutmeg grater apparance of dorsal aspect of digits
What are some associations or complicaitons of PRP?
Complications:
- Ectropion - dry eyes, belpharitis
- Erythroderma - causing temp instability, electrolyte disturbance, etc
- psychological distress and impact on QoL
- secondary infections: kaposi varicelliform eruption
Associations:
- eruptive Seb Ks
- Autoimmunity (hypothyroidism)
- Malignancy (paraneoplastic phenomenon)
- Viruses (HIV)
List some potential triggers for PRP?
- Viral infections - HIV
- Malignancy - paraneoplastic (?not much evidence for this) - solid organ malignancies
- UV exposure
- Trauma
- Drugs (TNF alfa, tyrosine kinase inhibiotrs)
- Vaccines
What would you tell a patient who has been diagnosed with PRP?
- Very rare condition
- In the vast majority of cases the cause is unknown (few cases are hereditary - these normally present in childhood)
- Treatment invovles
- creams and systemic meidcaiton
- Response to treatment is variable
- takes 3 - 6 months to know if a treatment is working - Very rarely caused by HIV or a medications
- HIV (will do a blood test)
- TNF alpha, tyrosine kinase inhibitor - Most people (80%) have spontaneous remission within 3 years
- Small risk of recurrence
What topical treatment would you suggest in PRP?
Emolliant
Medium - high potency topical CS (eg. betamethasone diproprionate 0.05%)
Keratolytic agent - 5% salycilic acid or 10 -20% urea
Avoid irritants, soap free wash etc
What are the first and second line systemic Rx for PRP? Include suggested dose.
- Oral Retinoids
* Acitretin 0.5 mg /kg/day
* Isotretinoin 0.5 - 1.0 mg /kg/day
* Takes 3 - 6 months for treatment effect - Methotrexate (oral or subcut)
* 5 - 25mg a week
* Takes 3 - 6 months for treatment effect
* Can be used in conjunction with oral retinoids
