INTRODUCTION :
World Health Organisation has defined a drug as “a substance or
product that is used or intended to be used to modify or explore
physiological system or pathological state of the recipient”.
Adverse drug reaction is defined by WHO as “a response to a drug
that is noxious, unintended and undesired and occurs at doses used in
man for modification of physiological function”. ADRs affect upto 7% of
the general population and constitute upto 8% of hospital admissions.
Cutaneous ADRs are among the more commonly observed adverse
reactions to medications. Among the various morphological drug reaction
patterns encountered, Fixed Drug Reactions account for upto one third of
cases. According to many Indian studies, Fixed drug eruption is the most
common cutaneous adverse drug reaction pattern, constituting 25-40% of
cases. In the western world, it is next only to maculopapular rash as
the common cause of CADR. Several studies analysing the
epidemiological, pathophysiological, pharmacological and clinical
aspects of FDE are available in literature. Though clinically less severe,
FDE causes cosmetic embarrassment in many patients.
AIMS OF THE STUDY :
To find out the incidence, age and sex distribution of Fixed Drug
Eruption among patients attending the Department of
Dermatology, Government General Hospital, Chennai.
* To find out the proportion of FDE cases among various cutaneous
adverse drug reactions.
* To find out the common offending drugs and study the drug
specific clinical patterns and sites of involvement in the FDE cases.
* To study the different parameters of fixed drug reaction - Number
of episodes in a patient and mean length of time from drug
exposure to the development of FDE lesions during initial and
subsequent episodes.
* To confirm the drugs responsible for causation through patch
testing.
* To study the various histopathological characteristics of fixed drug
eruptions.
* To ascertain the role of CD8+ T-cells in causation through
Immunohistochemistry.
CONCLUSION :
1. The incidence of Fixed Drug Eruption among Dermatology OPD
attendees from Aug 2008 to Aug 2010 was found to be 0.54%.
2. The main age group affected was 21 – 30 years.
3. An almost equal sex incidence. was observed with the male to
female ratio being 1.23:1.
4. The incubation period observed during the first and subsequent
episodes was 13.4 days and 4.6hrs respectively.
5. The most common offenders were fluoroquinolones especially
ciprofloxacin seen in 14.5% of cases and levofloxacin in 10.5% of
cases. The next common offender was cotrimoxazole inducing
FDE in 11.8% of cases. Nonsteroidal antiinflammatory drugs were
the causative drugs in 19.73% of cases with diclofenac being the
main inducer followed by paracetamol.
6. Classical presentation was seen in 81.57% of cases. The other two
morphological patterns encountered were Bullous FDE(18.42%)
and Nonpigmenting FDE(1.33%).
7. Multifocal pattern was the most common pattern of distribution of
lesions. Solitary and generalised patterns were also encountered.
8. Extremities were the most frequently involved sites seen in 44.73%
of cases, followed in decreasing order of frequency by trunk, face,
oral mucosa, genital mucosa, lips and palms and soles.
9. There was no statistically significant difference between males and
females regarding the site of involvement . Clinically mucosal
lesions and lesions on the palms and soles were more commonly
encountered in males. Involvement of the lip was commonly seen
in females.
10. Though statistically insignificant, clinically significant associations
were observed regarding drug specific site of involvement.
Phenytoin induced FDE exclusively on the trunk. Paracetamol was
observed to induce bullous FDE preferentially on palms and soles
Ciprofloxacin induced lesions mainly on the extremities.
11. The rate of occurrence of associated local and systemic symptoms
was 78.95% and 14.47% respectively which is relatively high when
compared to previous studies.
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12. Drug patch tests done to establish the causality of offending drugs
revealed positivity in 32.9% of patients. The testing was found to
be positive when done on lesional skin when compared to
nonlesional skin.
13. Histopathological examination of biopsy specimens produced
consististent findings in all the 33 cases in whom biopsy was
performed.
14. Immunohistochemical analysis done using antibodies to CD8
revealed positivity in both acute and chronic cases, establishing the
role of these cells in causation of FDE.
In the current study, the number of patients observed was less
when compared to the previous studies. So statistical analysis did not
reveal any significance regarding the sex specific and drug specific site
of involvement
