Skin Lesions in Patients Treated With Imatinib Mesylate: A 5-Year Prospective Study

Imatinib mesylate (IM) represents the first-line treatment of chronic myeloid leukemia (CML) and gastrointestinal stromal tumors (GISTs). Its pharmacological activity is related to a specific action on several tyrosine kinases in different tumors, including Bcr-Abl in CML, c-Kit (CD117) in GIST, and platelet-derived growth factor receptor in dermatofibrosarcoma protuberans.^1,2

Imatinib mesylate has been shown to improve progression-free survival and overall survival²; however, it also has several side effects. Among the adverse effects (AEs), less than 10% are nonhematologic, such as nausea, vomiting, diarrhea, muscle cramps, and cutaneous reactions.^3,4

We followed patients who were treated with IM for 5 years to identify AEs of therapy.

Methods

The aim of this prospective study was to identify and collect data regarding IM cutaneous side effects so that clinicians can detect AEs early and differentiate them from AEs caused by other medications. All patients were subjected to a median of 5 years’ follow-up. We included all the patients treated with IM and excluded patients who had a history of eczematous dermatitis, psoriasis, renal impairment, or dyshidrosis palmoplantar. Before starting IM, all patients presented for a dermatologic visit. They were subsequently evaluated every 3 months.

The incidence rate was defined as the ratio of patients with cutaneous side effects and the total patients treated with IM. Furthermore, we calculated the ratio between each class of patient with a specific cutaneous manifestation and the entire cohort of patients with cutaneous side effects related to IM.

When necessary, microbiological, serological, and histopathological analyses were performed.

Results

In 60 months, we followed 220 patients treated with IM. Among them, 55 (25%) developed cutaneous side effects (35 males; 20 females). The incidence rate of the patients with cutaneous side effects was 1:4. The median age of the entire cohort was 52.5 years. Fifty patients were being treated for CML and 5 for GISTs. All patients received IM at a dosage of 400 mg daily.

The following skin diseases were observed in patients treated with IM (Table): 19 patients with maculopapular rash with pruritus (no maculopapular rash without pruritus was detected), 7 patients with eczematous dermatitis such as stasis dermatitis and seborrheic dermatitis, 6 patients with onychodystrophy melanonychia (Figure 1), 5 patients with psoriasis, 5 patients with skin cancers including basal cell carcinoma (BCC)(Figure 2), 3 patients with periorbital edema (Figure 3), 3 patients with mycosis, 3 patients with dermatofibromas, 2 patients with dyshidrosis palmoplantar, 1 patient with pityriasis rosea–like eruption (Figure 4), and 1 patient with actinic keratoses on the face. No hypopigmentation or hyperpigmentation, excluding the individual case of melanonychia, was observed.

All cutaneous diseases reported in this study appeared after IM therapy (median, 3.8 months). The median time to onset for each cutaneous disorder is reported in the Table. During the first dermatologic visit before starting IM therapy, none of the patients showed any of these cutaneous diseases.

The adverse cutaneous reactions were treated with appropriate drugs. Generally, eczematous dermatitis was treated using topical steroids, emollients, and oral antihistamines. In patients with maculopapular rash with pruritus, oral corticosteroids (eg, betamethasone 3 mg daily or prednisolone 1 mg/kg) in association with antihistamine was necessary. Psoriasis was completely improved with topical betamethasone 0.5 mg and calcipotriol 50 µg. Skin cancers were treated with surgical excision with histologic examination. All treatments are outlined in the Table.

Imatinib mesylate therapy was suspended in 2 patients with maculopapular rash with moderate to severe pruritus; however, despite the temporary suspension of the drug and the appropriate therapies (corticosteroids and antihistamines), cutaneous side effects reappeared 7 to 10 days after therapy resumed. Therefore, the treatment was permanently suspended in these 2 cases and IM was replaced with erlotinib, a second-generation Bcr-Abl tyrosine kinase inhibitor.

Comment

The introduction of IM for the treatment of GIST and CML has changed the history of these diseases. The drug typically is well tolerated and few patients have reported severe AEs. Mild skin reactions are relatively frequent, ranging from 7% to 21% of patients treated.³ In our case, the percentage was relatively higher (25%), likely because of close monitoring of patients, with an increase in the incidence rate.

Imatinib mesylate cutaneous reactions are dose dependent.⁴ Indeed, in all our cases, the cutaneous reactions arose with an IM dosage of 400 mg daily, which is compatible with the definition of dose-independent cutaneous AEs.

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.

Imatinib mesylate (IM) represents the first-line treatment of chronic myeloid leukemia (CML) and gastrointestinal stromal tumors (GISTs). Its pharmacological activity is related to a specific action on several tyrosine kinases in different tumors, including Bcr-Abl in CML, c-Kit (CD117) in GIST, and platelet-derived growth factor receptor in dermatofibrosarcoma protuberans.^1,2

Imatinib mesylate has been shown to improve progression-free survival and overall survival²; however, it also has several side effects. Among the adverse effects (AEs), less than 10% are nonhematologic, such as nausea, vomiting, diarrhea, muscle cramps, and cutaneous reactions.^3,4

We followed patients who were treated with IM for 5 years to identify AEs of therapy.

Methods

The aim of this prospective study was to identify and collect data regarding IM cutaneous side effects so that clinicians can detect AEs early and differentiate them from AEs caused by other medications. All patients were subjected to a median of 5 years’ follow-up. We included all the patients treated with IM and excluded patients who had a history of eczematous dermatitis, psoriasis, renal impairment, or dyshidrosis palmoplantar. Before starting IM, all patients presented for a dermatologic visit. They were subsequently evaluated every 3 months.

The incidence rate was defined as the ratio of patients with cutaneous side effects and the total patients treated with IM. Furthermore, we calculated the ratio between each class of patient with a specific cutaneous manifestation and the entire cohort of patients with cutaneous side effects related to IM.

When necessary, microbiological, serological, and histopathological analyses were performed.

Results

In 60 months, we followed 220 patients treated with IM. Among them, 55 (25%) developed cutaneous side effects (35 males; 20 females). The incidence rate of the patients with cutaneous side effects was 1:4. The median age of the entire cohort was 52.5 years. Fifty patients were being treated for CML and 5 for GISTs. All patients received IM at a dosage of 400 mg daily.

The following skin diseases were observed in patients treated with IM (Table): 19 patients with maculopapular rash with pruritus (no maculopapular rash without pruritus was detected), 7 patients with eczematous dermatitis such as stasis dermatitis and seborrheic dermatitis, 6 patients with onychodystrophy melanonychia (Figure 1), 5 patients with psoriasis, 5 patients with skin cancers including basal cell carcinoma (BCC)(Figure 2), 3 patients with periorbital edema (Figure 3), 3 patients with mycosis, 3 patients with dermatofibromas, 2 patients with dyshidrosis palmoplantar, 1 patient with pityriasis rosea–like eruption (Figure 4), and 1 patient with actinic keratoses on the face. No hypopigmentation or hyperpigmentation, excluding the individual case of melanonychia, was observed.

All cutaneous diseases reported in this study appeared after IM therapy (median, 3.8 months). The median time to onset for each cutaneous disorder is reported in the Table. During the first dermatologic visit before starting IM therapy, none of the patients showed any of these cutaneous diseases.

The adverse cutaneous reactions were treated with appropriate drugs. Generally, eczematous dermatitis was treated using topical steroids, emollients, and oral antihistamines. In patients with maculopapular rash with pruritus, oral corticosteroids (eg, betamethasone 3 mg daily or prednisolone 1 mg/kg) in association with antihistamine was necessary. Psoriasis was completely improved with topical betamethasone 0.5 mg and calcipotriol 50 µg. Skin cancers were treated with surgical excision with histologic examination. All treatments are outlined in the Table.

Imatinib mesylate therapy was suspended in 2 patients with maculopapular rash with moderate to severe pruritus; however, despite the temporary suspension of the drug and the appropriate therapies (corticosteroids and antihistamines), cutaneous side effects reappeared 7 to 10 days after therapy resumed. Therefore, the treatment was permanently suspended in these 2 cases and IM was replaced with erlotinib, a second-generation Bcr-Abl tyrosine kinase inhibitor.

Comment

The introduction of IM for the treatment of GIST and CML has changed the history of these diseases. The drug typically is well tolerated and few patients have reported severe AEs. Mild skin reactions are relatively frequent, ranging from 7% to 21% of patients treated.³ In our case, the percentage was relatively higher (25%), likely because of close monitoring of patients, with an increase in the incidence rate.

Imatinib mesylate cutaneous reactions are dose dependent.⁴ Indeed, in all our cases, the cutaneous reactions arose with an IM dosage of 400 mg daily, which is compatible with the definition of dose-independent cutaneous AEs.

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.

Imatinib mesylate (IM) represents the first-line treatment of chronic myeloid leukemia (CML) and gastrointestinal stromal tumors (GISTs). Its pharmacological activity is related to a specific action on several tyrosine kinases in different tumors, including Bcr-Abl in CML, c-Kit (CD117) in GIST, and platelet-derived growth factor receptor in dermatofibrosarcoma protuberans.^1,2

Imatinib mesylate has been shown to improve progression-free survival and overall survival²; however, it also has several side effects. Among the adverse effects (AEs), less than 10% are nonhematologic, such as nausea, vomiting, diarrhea, muscle cramps, and cutaneous reactions.^3,4

We followed patients who were treated with IM for 5 years to identify AEs of therapy.

Methods

The aim of this prospective study was to identify and collect data regarding IM cutaneous side effects so that clinicians can detect AEs early and differentiate them from AEs caused by other medications. All patients were subjected to a median of 5 years’ follow-up. We included all the patients treated with IM and excluded patients who had a history of eczematous dermatitis, psoriasis, renal impairment, or dyshidrosis palmoplantar. Before starting IM, all patients presented for a dermatologic visit. They were subsequently evaluated every 3 months.

The incidence rate was defined as the ratio of patients with cutaneous side effects and the total patients treated with IM. Furthermore, we calculated the ratio between each class of patient with a specific cutaneous manifestation and the entire cohort of patients with cutaneous side effects related to IM.

When necessary, microbiological, serological, and histopathological analyses were performed.

Results

In 60 months, we followed 220 patients treated with IM. Among them, 55 (25%) developed cutaneous side effects (35 males; 20 females). The incidence rate of the patients with cutaneous side effects was 1:4. The median age of the entire cohort was 52.5 years. Fifty patients were being treated for CML and 5 for GISTs. All patients received IM at a dosage of 400 mg daily.

The following skin diseases were observed in patients treated with IM (Table): 19 patients with maculopapular rash with pruritus (no maculopapular rash without pruritus was detected), 7 patients with eczematous dermatitis such as stasis dermatitis and seborrheic dermatitis, 6 patients with onychodystrophy melanonychia (Figure 1), 5 patients with psoriasis, 5 patients with skin cancers including basal cell carcinoma (BCC)(Figure 2), 3 patients with periorbital edema (Figure 3), 3 patients with mycosis, 3 patients with dermatofibromas, 2 patients with dyshidrosis palmoplantar, 1 patient with pityriasis rosea–like eruption (Figure 4), and 1 patient with actinic keratoses on the face. No hypopigmentation or hyperpigmentation, excluding the individual case of melanonychia, was observed.

All cutaneous diseases reported in this study appeared after IM therapy (median, 3.8 months). The median time to onset for each cutaneous disorder is reported in the Table. During the first dermatologic visit before starting IM therapy, none of the patients showed any of these cutaneous diseases.

The adverse cutaneous reactions were treated with appropriate drugs. Generally, eczematous dermatitis was treated using topical steroids, emollients, and oral antihistamines. In patients with maculopapular rash with pruritus, oral corticosteroids (eg, betamethasone 3 mg daily or prednisolone 1 mg/kg) in association with antihistamine was necessary. Psoriasis was completely improved with topical betamethasone 0.5 mg and calcipotriol 50 µg. Skin cancers were treated with surgical excision with histologic examination. All treatments are outlined in the Table.

Imatinib mesylate therapy was suspended in 2 patients with maculopapular rash with moderate to severe pruritus; however, despite the temporary suspension of the drug and the appropriate therapies (corticosteroids and antihistamines), cutaneous side effects reappeared 7 to 10 days after therapy resumed. Therefore, the treatment was permanently suspended in these 2 cases and IM was replaced with erlotinib, a second-generation Bcr-Abl tyrosine kinase inhibitor.

Comment

The introduction of IM for the treatment of GIST and CML has changed the history of these diseases. The drug typically is well tolerated and few patients have reported severe AEs. Mild skin reactions are relatively frequent, ranging from 7% to 21% of patients treated.³ In our case, the percentage was relatively higher (25%), likely because of close monitoring of patients, with an increase in the incidence rate.

Imatinib mesylate cutaneous reactions are dose dependent.⁴ Indeed, in all our cases, the cutaneous reactions arose with an IM dosage of 400 mg daily, which is compatible with the definition of dose-independent cutaneous AEs.

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.