Drug Eruption and Interactions - PHARMACEUTICAL REVIEW

DESCRIPTIONS OF THE 34 MOST COMMON REACTION
PATTERNS
Acanthosis nigricans
Acanthosis nigricans (AN) is a process characterized by a
soft, velvety, brown or grayish-black thickening of the skin
that is symmetrically distributed over the axillae, neck, inguinal
areas and other body folds.
While most cases of AN are seen in obese and
prepubertal children, it can occur as a marker for various
endocrinopathies as well as in female patients with elevated
testosterone levels, irregular menses, and hirsutism.
It is frequently a concomitant of an underlying malignant
condition, principally an adenocarcinoma of the intestinal
tract.
Acneform lesions
Acneform eruptions are inflammatory follicular reactions
that resemble acne vulgaris and that are manifested clinically
as papules or pustules. They are monomorphic reactions,
have a monomorphic appearance, and are found primarily
on the upper parts of the body. Unlike acne vulgaris, there
are rarely comedones present. Consider a drug-induced
acneform eruption if:
• The onset is sudden
There is a worsening of existing acne lesions
The extent is considerable from the outset
The appearance is monomorphic
The localization is unusual for acne as, for example, when
the distal extremities are involved
The patient’s age is unusual for regular acne
There is an exposure to a potentially responsible drug.
The most common drugs responsible for acneform eruptions
are: ACTH, androgenic hormones, anticonvulsants
(hydantoin derivatives, phenobarbital, trimethadione),
corticosteroids, danazol, disulfiram, halogens (bromides,
chlorides, iodides), lithium, oral contraceptives,
tuberculostatics (ethionamide, isoniazid, rifampin), vitamins
B2, B6, and B12.
Acute generalized exanthematous pustulosis
Arising on the face or intertriginous areas, acute generalized
exanthematous pustulosis (AGEP) is characterized by a rapidly
evolving, widespread, scarlatiniform eruption covered
with hundreds of small superficial pustules.
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Often accompanied by a high fever, AGEP is most frequently
associated with penicillin and macrolide antibiotics,
and usually occurs within 24 hours of the drug exposure.
Alopecia
Many drugs have been reported to occasion hair loss. Commonly
appearing as a diffuse alopecia, it affects women more
frequently than men and is limited in most instances to the
scalp. Axillary and pubic hairs are rarely affected except with
anticoagulants.
The hair loss from cytostatic agents, which is dosedependent
and begins about 2 weeks after the onset of therapy,
is a result of the interruption of the anagen (growing)
cycle of hair. With other drugs the hair loss does not begin
until 2–5 months after the medication has been begun. With
cholesterol-lowering drugs, diffuse alopecia is a result of
interference with normal keratinization.
The scalp is normal and the drug-induced alopecia is
almost always reversible within 1–3 months after the therapy
has been discontinued. The regrown hair is frequently
depigmented and occasionally more curly.
The most frequent offenders are cytostatic agents and
anticoagulants, but hair loss can occur with a variety of common
drugs, including hormones, anticonvulsants,
amantadine, amiodarone, captopril, cholesterol-lowering
drugs, cimetidine, colchicine, etretinate, isotretinoin,
ketoconazole, heavy metals, lithium, penicillamine, valproic
acid, and propranolol.
Angioedema
Angioedema is a term applied to a variant of urticaria in
which the subcutaneous tissues, rather than the dermis, are
mainly involved.
Also known as Quincke’s edema, giant urticaria, and
angioneurotic edema, this acute, evanescent, skin-colored,
circumscribed edema usually affects the most distensible tissues:
the lips, eyelids, earlobes, and genitalia. It can also affect
the mucous membranes of the tongue, mouth, and larynx.
Symptoms of angioedema, frequently unilateral, asymmetrical
and non-pruritic, last for an hour or two but can
persist for 2–5 days.
The etiological factors associated with angioedema are as
varied as that of urticaria (which see).