Maculopapular eruptions, drug-induced

Hypersensitivity reactions with P-lactam antibiotics, especially penicillin, may encompass any of the type I through IV Gell-Coombs classifications. The most common reactions are maculopapular and urticarial eruptions.7 While rare (less than 0.05%), anaphylaxis to penicillins causes the greatest concern because they are responsible for the majority of drug-induced anaphylaxis deaths in patients, accounting for 75% of all ana-i phylaxis cases in the United States.5,8 The treatment of ana-I phylaxis is given in Table 51-2.9... 

The word dermatitis denotes an inflammatory erythematous rash. The disorders discussed in this chapter include contact dermatitis, seborrheic dermatitis, diaper dermatitis, and atopic dermatitis. Drug-induced skin disorders have been associated with most commonly used medications and may present as maculopapular eruptions, fixed-drug eruptions, and photosensitivity reactions. 

A 29-year-old man developed an infiltrative maculo-papular eruption after 1 week of itraconazole 100 mg bd for tinea corporis (44). Itraconazole was withdrawn, and the lesions disappeared within 7 days. Scratch tests, patch tests, scratch-patch tests, and drug induced lymphocyte stimulation tests for itraconazole were negative however, rechallenge with systemic itraconazole induced a maculopapular eruption on the face, hands, and the dorsa of the feet. Empty itraconazole capsules had no cutaneous effects, suggesting an allergic reaction to a metabolite of the compound. 

At present, the ampicillins must be regarded as the commonest cause of drug-induced maculopapular eruptions. Rashes develop in an average of 10% of patients treated with ampicillin. As already mentioned, the underlying disease, and possibly the dose as well, has an unmistakable influence on the frequency of rashes. Kennedy et al. (1963) found higher incidences in salmonellosis than in other bacterial infections. In infectious mononucleosis the incidence of rashes is said to be 90%-100%. 

The possible association between HLA-B 1502 and carbamazepine- or phenytoin-induced Stevens-Johnson syndrome or maculopapular eruptions has been explored in 31 Thai subjects who had these antiepileptic drug-induced complications between 1994 and 2007 and in 50 antiepileptic drug-tolerant controls [92. There was a strong association between HLA-B 1502 and phenytoin- and carbamazepine-induced Stevens-Johnson syndrome. However, some patients with HLA-B 1502 had had carbamazepine-induced Stevens-Johnson syndrome and were tolerant of phenytoin and vice versa, which suggests that other factors contribute to this adverse reaction. 

Non-immediate reactions to quinolones occur but they are not encountered as often as immediate reactions and in-depth studies are so far few. Some of the more often-seen delayed reactions are fixed drug eruptions and maculopapular exanthemas where a T cell mechanism has been demonstrated. Specific T cell clones were identified from patients with ciprofloxacin-induced maculopapular exanthems and about half of the clones proved cross-reactive with related drugs. Reexposure studies in patients with exanthems revealed that cross-reactivity is in fact lower than this. Cellular tests such as lymphocyte transformation tests were judged to be not very useful. However, the lymphocyte transformation test was said to have confirmed the involvement of T cells when peripheral blood... 

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