Efficacy of isotretinoin in pityriasis rubra pilaris: unapproved use

Oral isotretinoin for the treatment of dermatologic conditions other than acne: a systematic review and discussion of future directions

While isotretinoin has been the gold-standard of therapy for severe acne since its approval in 1982, its anti-inflammatory properties makes it a potentially applicable and versatile therapy for a wide variety of dermatologic conditions yet to be explored. This systematic review comprehensively recounts the success of oral isotretinoin in non-acne cutaneous diseases and provide insight into future directions of isotretinoin utility. A systematic literature review was performed using PubMed. Search terms included "isotretinoin" OR "accutane" AND "skin" OR "dermatology" OR "hair" OR "nails" OR "rosacea" OR "psoriasis" OR "pityriasis rubra pilaris" OR "condyloma acuminata" OR "granuloma annulare" OR "darier's disease" OR "non-melanoma skin cancer" OR "frontal fibrosing alopecia" OR "cutaneous lupus erythematosus" OR "hidradenitis suppurativa" OR "photodamaged skin" OR "skin aging" OR "wart" OR "flat warts" OR "plane warts" OR "lichen planus" OR "dissecting cellulitis" OR "folliculitis decalvans" OR "sebaceous hyperplasia" OR "cutaneous t-cell lymphoma" OR "mycosis fungoides." A total of 169 studies discuss the use of oral isotretinoin for 16 non-acne dermatologic conditions, the most common being non-melanoma skin cancers (0.2-8.2 mg/kg/day), cutaneous T-cell lymphomas (0.5-2 mg/kg/day), and rosacea (0.22-1 mg/kg/day). Inflammatory conditions such as rosacea, granuloma annulare, and hidradenitis suppurativa benefit from lower oral isotretinoin dosage of 0.3-1 mg/kg/day, whereas, hyperkeratotic diseases such as psoriasis and pityriasis rubra pilaris, consistently respond better to higher dosages of up to 2-4 mg/kg/day for lesion clearance. Recurrence of disease following discontinuation of isotretinoin have been reported for rosacea, psoriasis, granuloma annulare, Darier's disease, dissecting cellulitis, and non-melanoma skin cancers. Disease exacerbation was reported in some patients with hidradenitis suppurativa. Off-label isotretinoin is an effective treatment choice for dermatological conditions beyond acne. Further prospective, randomized human trials are needed to clarify when and how to prescribe off-label isotretinoin for maximum efficacy and safety.

Systemic therapies of pityriasis rubra pilaris: a systematic review

Pityriasis rubra pilaris (PRP) is a rare papulosquamous disorder. Treatment is challenging; the armamentarium consists of topical corticosteroids, phototherapy, classic systemic treatments such as retinoids or immunosuppressive drugs, and most recently biologicals. However, the relative effectiveness of therapies is unclear. Our objective was to review the published literature on systemic treatment of PRP. A systematic review was conducted on PubMed and the Cochrane Library up to 5 September 2017. Studies evaluating any systemic treatments of PRP (except for historical treatments) were included. Overall, 182 studies met the predefined inclusion criteria, and reported on 475 patients and 652 courses of treatment. 42.0 % (225/514) of all patients treated with retinoids achieved an excellent response (isotretinoin: 61.1 % [102/167], etretinate: 47 % [54/115], and acitretin: 24.7 % [43/174]) compared to an excellent response rate of 33.1 % (53/160) with methotrexate. Therapy with biologicals was successful in 51.0 % of patients (71/133) (ustekinumab: 62.5 % [10/16], infliximab: 57.1 % [28/49], etanercept: 53.3 % [16/30], and adalimumab: 46.4 % [13/28]). This review balances effectiveness, side effects, experience, and drug costs in order to suggest a treatment regimen starting with isotretinoin as first-line, methotrexate as second-line and biologicals as third-line treatment for this difficult-to-treat dermatosis.