The most common cutaneous AEs reported in the literature were swelling/edema and maculopapular rash. Swelling is the most common AE described during therapy with IM with an incidence of 63% to 84%.5 Swelling often involves the periorbital area and occurs approximately 6 weeks after starting IM. Although its pathogenesis is uncertain, it has been shown that IM blocks the platelet-derived growth factor receptor expressed on blood vessels that regulates the transportation transcapillary. The inhibition of this receptor can lead to increased pore pressure, resulting in edema and erythema. Maculopapular eruptions (50% of cases) often affect the trunk and the limbs and are accompanied by pruritus. Commonly, these rashes arise after 9 weeks of IM therapy. These eruptions are self-limiting and only topical emollients and steroids are required, without any change in IM schedule. To treat maculopapular eruptions with pruritus, oral steroids and antihistamines may be helpful, without suspending IM treatment. When grade 2 or 3 pruriginous maculopapular eruptions arise, the suspension of IM combined with steroids and antihistamines may be necessary. When the readministration of IM is required, it is mandatory to start IM at a lower dose (50–100 mg/d), administering prednisolone 0.5 to 1.0 mg/kg daily. Then, the steroid gradually can be tapered.6 Critical cutaneous AEs that are resistant to supportive measures warrant suspension of IM therapy. However, the incidence of this event is small (<1% of all patients).7
Regarding severe cutaneous AEs from IM therapy, Hsiao et al8 reported the case of Stevens-Johnson syndrome. In this case, IM was immediately stopped and systemic steroids were started. Rarely, erythroderma (grade 4 toxicity) can develop for which a prompt and perpetual suspension of IM is necessary and supportive care therapy with oral and topical steroids is recommended.9
Hyperpigmentation induced by IM, mostly in patients with Fitzpatrick skin types V to VI and with a general prevalence of 16% to 40% in treated patients, often is related to a mutation of c-Kit or other kinases that are activated rather than inhibited by the drug, resulting in overstimulation of melanogenesis.10 The prevalence of Fitzpatrick skin types I to III determined the absence of pigmentation changes in our cohort, excluding melanonychia. Hyperpigmentation was observed in the skin as well as the appendages such as nails, resulting in melanonychia (Figure 1). However, Brazzelli et al11 reported hypopigmentation in 5 white patients treated with IM; furthermore, they found a direct correlation between hypopigmentation and development of skin cancers in these patients. The susceptibility to develop skin cancers may persist, even without a clear manifestation of hypopigmentation, as reported in the current analysis. We documented BCC in 5 patients, 1 patient developed actinic keratoses, and 3 patients developed dermatofibromas. However, these neoplasms probably were not provoked by IM. On the contrary, we did not note squamous cell carcinoma, which was reported by Baskaynak et al12 in 2 CML patients treated with IM.
The administration of IM can be associated with exacerbation of psoriasis. Paradoxically, in genetically predisposed individuals, tumor necrosis factor α (TNF-α) antagonists, such as IM, seem to induce psoriasis, producing IFN-α rather than TNF-α and increasing inflammation.13 In fact, some research shows induction of psoriasis by anti–TNF-α drugs.14-16 Two cases of IM associated with psoriasis have been reported, and both cases represented an exacerbation of previously diagnosed psoriasis.13,17 On the contrary, in our analysis we reported 5 cases of psoriasis vulgaris induced by IM administration. Our patients developed cutaneous psoriatic lesions approximately 1.7 months after the start of IM therapy.
The pityriasis rosea–like eruption (Figure 4) presented as nonpruritic, erythematous, scaly patches on the trunk and extremities, and arose 3.6 months after the start of treatment. This particular cutaneous AE is rare. In 3 case reports, the IM dosage also was 400 mg daily.18-20 The pathophysiology of this rare skin reaction stems from the pharmacological effect of IM rather than a hypersensitivity reaction.18
Deininger et al7 reported that patients with a high basophil count (>20%) rarely show urticarial eruptions after IM due to histamine release from basophils. Premedication with an antihistamine was helpful and the urticarial eruption resolved after normalization in basophil count.7
Given the importance of IM for patients who have limited therapeutic alternatives for their disease and the ability to safely treat the cutaneous AEs, as demonstrated in our analysis, the suspension of IM for dermatological complications is necessary only in rare cases, as shown by the low number of patients (n=2) who had to discontinue therapy. The cutaneous AEs should be diagnosed and treated early with less impact on chemotherapy treatments. The administration of IM should involve a coordinated effort among oncologists and dermatologists to prevent important complications.
