pityriasis rubra pilaris ( prp ) includes a spectrum of rare chronic , idiopathic inflammatory disorders with papulosquamous eruptions of unknown cause .
prp shows consistent clinical heterogeneity ; consequently , it is hard to predict the outcome of treatment .
a 29-year - old female presented for evaluation of a skin condition previously diagnosed as psoriasis vulgaris .
the lesions first appeared at age six years with no preceding trauma or infection and were characterized by palmoplantar keratoderma and demarcated , hyperkeratotic plaques on the elbows and knees .
the patient had been on many systemic treatments over the last two years without response , including cyclosporine ( 3 mg / kg / day for 3 months ) , methotrexate ( 15 mg / weekly for 4 months ) , adalimumab ( two subcutaneous injection of 40 mg at day 0 , a subcutaneous injection of 40 mg at day 7 and every 14 days thereafter for 16 weeks ) , etanercept ( 50 mg weekly subcutaneous injections for 12 weeks ) , infliximab ( 5 mg / kg given as an intravenous infusion at weeks 0 , 2 , 8) .
physical examination showed a diffuse , orange - pink palmoplantar keratoderma [ figure 1 ] .
well - defined keratotic follicular papules also involved the dorsal aspects of the hands and feet , elbows and knees [ figures 2 and 3 ] .
a skin biopsy revealed alternating parakeratosis and orthokeratosis , pronounced irregular acanthosis , focal hypergranulosis and mild focal spongiosis .
based on clinical and histologic findings , the patient was diagnosed having prp , type iv ( circumscribed juvenile ) .
after voluntary , informed consent , ustekinumab 45 mg subcutaneously at weeks 0 and 4 , and quarterly thereafter ( patient 's weight = 55 kg ) was then started , the same posology as in psoriasis .
keratoderma of the hands with a sharp demarcation of the borders diffuse transgrediens palmoplantar keratoderma on the dorsum of hands follicular hyperkeratosis and erythema on the elbows alternating parakeratosis and orthokeratosis , irregular acanthosis , focal hypergranulosis and a perivascular lymphocytic infiltration in the papillary dermis ( h and e 10 )
pityriasis rubra pilaris occurs equally in male and female patients , with a bimodal age distribution , peaking during the first and then the sixth decade .
griffiths proposed a classification for prp in five subtypes , based upon age , duration , and type of cutaneous involvement .
type i , or classic prp , is the commonest type ( 50% of cases ) and occurs in adults .
the patient is usually erythrodermic with diffuse thickening of the palms and soles and possibly ectropion .
80% of patients experience clinical resolution within 3 years . on the basis of griffith 's classification
clinical manifestations occurred in her prepubertal age and relapsed at age 27 , after a long - lasting remission .
type iv prp develops in prepubertal children presenting with sharply - demarcated areas of follicular hyperkeratosis and erythema on the elbows and knees . a waxy , orange - red , diffuse , palmoplantar keratoderma is also commonly observed .
a standard therapeutic approach does not exist as cases are few and treatment is protracted .
an increasing number of reports document the effectiveness of tumor necrosis factor- ( tnf- ) blockers in recalcitrant prp .
further , some case reports have documented favorable response of prp to ustekinumab , a fully human monoclonal antibody which binds to interleukin-12 ( il-12 ) and il-23 with high specificity and affinity .
an upregulation of tnf mrna in lesional compared with nonlesional skin in two patients with type i prp has been demonstrated .
a recent retrospective revision investigating treatment options showed a marked clinical in more than 50% of patients with type
, a systematic review of reports of prp responding positively to tnf- blockers does not recommend them due to possible reporting bias and spontaneous remissions . in the literature ,
the patients who achieved remission with tnf- blockers or ustekinumab were all consistent with classical type 1 prp .
our patient who presented a type iv prp was unresponsive to the tnf - blockers adalimumab , etanercept and infliximab .
our clinical experience suggests that in patients with type iv prp , tnf and il-12/il-23 blockade may not be useful targets .
since we observed a primary lack of response to all available tnf - blockers , we suggest that yet unmapped signaling pathways may be involved in type iv prp .
there seems to be inadequate response of circumscribed variants of prp to standard therapies that are effective in classical prp .
 treatment of pityriasis rubra pilaris ( prp ) may be difficult since no standardized therapeutic approach has been established . 
 recently , tumor necrosis factor- ( tnf- ) blockers have been demonstrated to be favorable in the management of recalcitrant prp . 
 the authors report a case of a patient who presented a type iv prp or circumscribed , juvenile type . 
 such a condition follows an unpredictable course , presenting with diffuse , palmoplantar keratoderma and sharply - demarcated areas of follicular hyperkeratosis on the elbows and knees . 
 treatment with all available tnf- inhibitors and ustekinumab did not prove to be helpful . 
 the authors suggest that circumscribed variants of prp could respond to therapy in ways different from classical prp . 