A misdiagnosed skin disease
Three years ago, MG developed a miliaria kind of rash (parang bungang araw). At first, MG just ignored the rashes. Two months later, the papules (butlig-butlig) developed into bigger rashes, which MG described as nagpantal-pantal. She went to a physician who told her she has Multibacillary Hansen’s disease or leprosy (ketong), based on the number of drugs she was asked to take. MG was then prescribed a multi-drug therapy (MDT — three kinds of drugs taken all together) for leprosy without the benefit of a skin biopsy. After taking the drugs, the patient developed blisters (like the rash of chicken pox) and two weeks later, the blisters appeared to have been infected. She went back to the doctor who advised her to continue the drugs as the doctor thought she was in reaction. In leprosy, “in reaction†means that the patient is responding to the treatment well, but due to the breakdown of the bacterium, the body reacts by producing a more severe skin reaction. This severe reaction can be in the form of more nodules (mas maraming bukol-bukol) or the elevation and enlargement of the flat lesions becoming more prominent. So MG took the drug for a total of eight months, which produced generalized, large ulcerations with severe, hardened crusts (langib) covering and surrounding the ulcers. This was all over her body, with the majority of the ulcerations located on her lower back areas. MG became bedridden. She limited her activities due to the pain emanating from the large ulcerating wounds all over her body. Not knowing what to do, MG went back to the same doctor and was again advised to continue the MDT. But after doing so for a week, the lesions, which were originally just on the torso and limbs, now spread to her face.
Skin drug reactions are one of the most common types of adverse reaction to drug therapy, with an overall incidence rate of two to three percent. Any medicine can induce skin reactions. Non-steroidal anti-inflammatory drugs (NSAIDs), antibiotics, antiepileptics have drug eruption rates approaching one to five percent. Although most drug-related skin eruptions are not serious, some are severe and potentially life- threatening. Serious reactions include angioedema (swollen eyes, lips, palms, and soles of feet), erythroderma (peeling of skin all over the body, causing generalized redness), Stevens-Johnson Syndrome, and toxic epidermal necrolysis (the latter two are the most scary). Drug eruptions can also occur as part of a spectrum of multiorgan involvement, as in drug-induced systemic lupus erythematosus.
A cutaneous drug reaction should be suspected in any patient who develops a rash during the course of drug therapy. The reaction may be due to any medicine the patient is currently taking or has recently been exposed to, including prescribed and over-the-counter medicines, herbal or homoeopathic preparations, vaccines or contrast media (used in X-ray , CT scan). Also remember that the non-drug component of a medicine (coloring, preservatives, etc.) may also cause hypersensitivity reactions in some patients.
It can be difficult to diagnose a drug eruption with confidence as most drugs are associated with a spectrum of skin reactions. Many of these drug eruptions cannot be distinguished from naturally occurring eruptions, and so a misdiagnosis is common. Another case would be the uncertainty as to whether a morbilliform rash is due to a viral infection or antibiotic, because they can look exactly alike. Furthermore, patients may be taking several medicines, making it difficult to establish the culprit. The timing of the reaction is a useful diagnostic tool. In general, the onset occurs within a few weeks of the introduction of the causative drug. If a medicine has been taken for many years without a problem, then it is less likely to be responsible. So, when examining a list of medicines taken by a patient with a rash, new drugs taken within the previous months are the most likely cause except for some notable exceptions as in penicillin, whose reaction can occur several weeks after the drug has been discontinued. Also, as in the case of beta blockers (e.g. inderal, practolol), reactions generally occur after many months of intake.
In the case of MG, her presentation is more of the vasculitic type. Several drugs can induce both systemic vasculitis and cutaneous manifestation without another organ involvement. About 10 percent of cutaneous vasculitis is believed to be drug-induced. It presents usually with purpura (purple, red spots) or with hemorrhagic blisters plus ulceration that can appear on the buttocks, extremities, and the trunk. Symptoms, such as malaise (generalized weakness), arthralgia, and fever, may occur but are less common.
Drug-induced reactions can present themselves as: exanthema (very red rashes all over the body), erythroderma (severe exfoliation all over, causing generalized redness), fixed drug eruption (rashes on the same site everytime), psoriasis-like eruptions, purpura (blood underneath the skin), blistering eruptions, photosensitivity eruptions, pigmentary disorder, alopecia or decrease in hair, nail disorder.
In the case of MG, her skin biopsy was suggestive of a bullous drug eruption or an autoimmune blistering disease. To rule out the latter, an immunofluorescence test was done, which also was suggestive of a drug-induced pathology. Additional tests were no longer done as the patient was on her way to almost full recovery.
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