Etiologies
- Inflammatory dermatoses
- Psoriasis (60%)
- Atopic dermatitis (5%)
- Pityriasis rubra pilaris (<5%)
- Polymorphic light eruption (<5%)
- Dermatitis other than atopic
- Lichen planus
- Chronic actinic dermatitis
- Papuloerythroderma of Ofuji
- Sarcoidosis
- Adverse drug reaction (15-20%)
- ACE inhibitor, particularly enalapril and lisinopril
- Allopurinol
- Bevacizumab
- Carbamazepine
- Chlorpromazine
- Dapsone
- Erythropoietin
- Gold salts
- Hydroxychloroquine
- Imatinib
- Isoniazid
- Penicillin
- Phenobarbital
- Phenytoin
- Piroxicam
- Proton pump inhibitor
- Retinoids, including acitretin and isotretinoin
- Streptomycin
- Sulfasalazine
- Terbinafine
- Thalidomide
- Co-trimoxazole
- Vancomycin
- Malignancy
- Hematologic
- Cutaneous T-cell lymphoma, including Sézary syndrome and mycosis fungoides (10-15%)
- Other lymphoma
- Leukemia
- Solid organ
- Hematologic
- Immunobullous disease
- Connective tissue diseases
- Infections
- Blood disorders
- Idiopathic