Stefano Caccavale1, Tobia Caccavale2, Maddalena La Montagna3. 1. Department of Dermatology, Second University of Naples, Naples, Italy. E-mail: stefano85med@libero.it. 2. Department of Cardiovascular Surgery and Transplant, Second University of Naples, Naples, Italy. 3. Department of Psychiatry, University of Foggia, Foggia, Italy.
Sir,We read with great interest the report recently published in the Indian Journal of Dermatology by Balasubramanian and Srinivas[1] which describes a patient with pustular psoriasis occurring on the striae distensae.[1] The patient complained recurrent episodes of generalized pustular eruptions since the age of 15 years. Since the disease was recalcitrant, the patient had assumed systemic steroids during an acute exacerbation, developing steroid-induced striae distensae over the anterior abdomen, arms, and thighs. The authors reported that the current episode of pustular psoriasis was characterized by the striking occurrence of pustular eruptions on the striae.[1]We speculate that Balasubramanian's report is no more than a further mere example of “immunocompromised cutaneous district” (ICD).[2] The injuring events capable of rendering a skin region a potential ICD are various, numerous, and most of the times identifiable using a careful clinical history.[23456789101112131415161718192021] An ample documentation of multifarious disorders appearing in ICDs was delineated by Ruocco et al. in 2009.[2] In the following 8 years, this concept has been extended to an enlarging variety of clinical conditions. A recent classification has proposed a newly coined terminology to indicate each specific cause responsible for the occurrence of an ICD and has encompassed additional conditions that had not been defined previously.[161718192021] The report of Balasubramanian and Srinivas can be seen as an example of isomorphic response or Köbner phenomenon (a preexisting disease that appears at site of injury), and neither an isotopic response (a new skin disease that appears at site of previously diseased or injured), nor an isoscartopic response, since the pustular psoriasis was preexistent to the development of striae distansae.[119] Disruption of lymph microcirculation and damage to peripheral nerve endings could obviously have been occurred in the patient's scared skin, thus altering the local interplay between immune cells conveyed by lymph vessels and neuromediators running along peripheral nerve fibers. Depending on which of the neurotransmitters and immune cells are involved, this destabilization can be either defective, thus predisposing to infections and tumors, or excessive, thus favoring the occurrence of some immune disorders or dysimmune reactions[2] (as pustular psoriasis).[22]We thank the authors for giving us the opportunity to discuss such a complex and interesting topic.