Disease concomitance in psoriasis: A clinical study of 61 cases

Introduction

The prevalence of other diseases associated with psoriasis has been investigated in recent years. These include cutaneous as well as systemic ones. The cutaneous diseases found to be associated include vitiligo, seborrhoeic dermatitis, bullous pemphigoid, photosensitive disorders, viral warts and others.[1] The systemic diseases found to be associated with psoriasis include diabetes, gout, ulcerative colitis, Crohn′s disease, cardiac insufficiency and others.[1] In view of the different cutaneous and systemic associations, a study was done on concomitant diseases which included 61 psoriatic and 61 age - and - sex - matched control patients from Dermatology department.

Materials and Methods

Sixty-one patients with psoriasis were stud-ied between January 96 and June 97, and were compared with sixty one age and sex-matched controls. History included details of psoriasis and concomitant cutaneous and systemic diseases. Detailed cutaneous and systemic examination were done. Relevant laboratory investigations were also done.

Results

Among the sixty-one patients with psoria-sis, the male to female ratio was 7.7:1. The maxi-mum incidence of psoriasis was in the age group of 40-50 years.

Psoriasis vulgaris was the most common clinical type of psoriasis (91.8%). Clinical types of psoriasis are shown in [Table - 1].

Among 61 patients with psoriasis, 3 had psoriatic arthritis and these 3 patients had psoriasis vulgaris. Among the three patients of psoriatic arthritis, two had classical type (3.2%) and one had symmetric polyarticular type (1.6%). In all the 3 the skin lesions preceded arthritis.

Various changes observed in the nails in the order of frequency, were pitting (63.9%), ridging (56.3%), discolouration (47.5%), subungual hyperkeratosis (29.5%), onycholysis (16.3%), onychodystrophy (4.9%) and leukonychia (3.2%).

[Table - 2] shows concomitant cutaneous diseases in patients with psoriasis. They included leucoderma, acne vulgaris, seborrhoeic dermatitis, forefoot eczema, sebaceous cyst, freckles, folliculi-tis, alopecia areata, candidiasis and acrochordon.

Concomitant systemic diseases are shown in [Table - 3]. Of the systemic disorders noted with psoriasis, diabetes mellitus showed the highest frequency with an O/E ratio of 2.6 (O/E ratio - observed by expected ratio).

Discussion

We have compared the simultaneous oc-currence of skin and systemic disorders in patients with psoriasis and in control patients without pso-riasis. As a result, a distinct group of cutaneous diseases were more frequently noted in patients with psoriasis than in age matched controls.

In our study of 61 patients 54 (88.5%) were males and 7 (11.4%) were females, which is in agreement with the male preponderance noted by (2.4% and 0.8%) many authors.[2],[3],[4]

Lichen simplex chronicus (-LSC) showed an O/E ratio of 10, which indicates that it is 10 times more common in patients with psoriasis. The high incidence of LSC in our study may be because of a bidirectional relationship i.e., if a psoriatic lesion itches, the lesion may become complicated by a lichen simplex or a lichen simplex can itch per se and the resultant rubbing may worsen the psoriasis.

Several common disorders were less fre-quent in patients with psoriasis such as eczemas, allergic contact dermatitis, urticaria, atopic derma-titis, bacterial, viral and fungal infection. This is an agreement with the study done by Henseler and Christopher.[5] According to Richard Weller,[6] the decreased incidence of skin infections caused by dermatophytes and particularly by bacteria and viruses is due to enhanced production of nitric oxide in psoriatic skin, which has antimicrobial activity against a wide range of organisms including bacteria, fungi and viruses.

Of the systemic disorders, diabetes showed the highest frequency with an O/E ratio of 2.6. This is in agreement with the study done by Sundharam[7] who showed a relationship between abnormal glucose tolerance and psoriasis.

In our study, 2 patients (3.25%) had HIV infection, and both the patients had severe and atypical lesions. This is in agreement with the find-ings of Obuch and Maurae that in HIV patients the different morphological types of psoriasis like papules, crusted and hyperkeratotic lesions co- exist. As the number of patients studied here is small, these findings have to be corroborated by studying a larger group.