Psoriasiform Drug Eruptions and Drugs That Flare Psoriasis

• Published in: Cutaneous Drug Eruptions pp. 141 - 155
• Main Authors: Lester, Elizabeth B., Cook, Deborah L., Frieling, Gretchen W.
• Format: Book Chapter
• Language: English
• Published: London Springer London 2015
• Subjects: Drug-induced psoriasis; Psoriasiform drug eruption; Psoriasiform drug reaction; Psoriasis
• ISBN: 1447167287; 9781447167280
• DOI: 10.1007/978-1-4471-6729-7_14

Drugs may exacerbate pre-existing psoriasis, induce new psoriatic lesions on previously uninvolved skin in patients with existing psoriasis, and precipitate de novo psoriasis in patients irrespective of a family history of psoriasis. The clinical spectrum includes limited or generalized erythematous plaques with thick, large, silvery scales, pustular lesions, or erythroderma. Histopathological examination demonstrates psoriasiform epidermal hyperplasia, parakeratosis with entrapped neutrophils, decreased granular cell layer, focal interface dermatitis, minimal and focal dyskeratosis, and a superficial perivascular lymphocytic inflammatory response with admixed histiocytes and eosinophils. A helpful distinguishing feature of drug-induced psoriasis is the absence of Munro microabscesses, langerhan cells, and vascular changes (tortuous papillary dermal capillaries and related suprapapillary epidermal thinning), with a tendency to exhibit more spongiosis and have less neutrophils and lymphocytes in the epidermis. An understanding and awareness of elements that may induce, trigger, or exacerbate the disease is of utmost importance in clinical practice today. As new drugs are constantly being developed, prescribed, and ultimately influencing disease progression, the knowledge and systematization of drugs and their potential reactions should be understood and acknowledged. Awareness of the clinicopathologic findings in specific drug reactions is essential in making a timely and correct diagnosis. In this chapter, we will discuss the drugs that have a strong association with psoriasis, a considerable association but with insufficient data, and those that are occasionally reported to be associated with aggravation or induction of psoriasis.