# Tumor Microenvironment and Dermatological Conditions in Prostate Cancer
## 2 The Cutaneous Manifestations Associated with PCa
### Adverse Cutaneous Drug Events in PCa Patients  
PCa treatment options include prostatectomy, radiotherapy, chemotherapy, immunotherapy, hormonal therapy, corticosteroids, and targeted therapy. The severity of drug-induced cutaneous adverse reactions is variable. Mild reactions to severe and sometimes even life-threatening forms were described. There are few articles in the literature that discuss these reactions [87; 88; 89; 90; 91; 92; 93; 94; 95].  
Radiotherapy can cause mild or severe changes in the skin (itching, erythema, edema, pigment spots, desquamation, wounds, infections, and alteration of the barrier function) and pathological changes in the nails (onychomycosis and melanonychia) [88; 89].  
Chemotherapy can induce cutaneous changes (minor or severe rash, photosensitivity, desquamation, itching, erythema, bullous lesions, hypersensitivity reactions, urticaria, and hypo/hyperpigmentation); hair changes (alopecia, seborrheic dermatitis, and hair fragility); and nail changes (onycholysis, subungual abscesses, onychoschizia, and brittle and cracked nails) [88,89].  
The effects of a response to immunotherapy (inhibitors of the programmed death receptor 1-PD-1) can be systematized as follows: changes in the mucous membranes (severe, extensive, and painful blisters); cutaneous changes (acneiform eruptions, dry or blistered skin, hand-foot syndrome, hypo/hyperpigmentation spots, eruptive melanocytic nevi, pruritus, keratoacanthoma, phototoxic and photoallergic reactions, erythema, and angioedema); nail changes (cracked and yellow nails, disorganized cuticles, melanonychia, and acute paronychia); and hair changes (alopecia areata) [87,88].  
Hormonal therapy for PCa (luteinizing hormone-releasing hormone agonists and antiandrogens) causes hypersensitivity reactions (anaphylaxis, urticaria, and angioedema), pruritus, arthalgia, hot flashes, peripheral edema, or acne vulgaris [87]. PCa patients treated with the androgen receptor inhibitor apaltumamide frequently develop skin rashes, distributed on the trunk, extremities, head/neck, and genitals. The most common cutaneous manifestations caused by androgen receptor inhibitor apaltumamide are as follows: xerosis, maculopapular rash, erythematous rash, eczematous rash, acneiform rash, psoriasis-form rash, urticaria, pruritus with/without rash, petechiae, alopecia, oral lichen planus [90], acute generalized exanthematous pustulosis, and Stevens-Johnson syndrome/toxic epidermal necrolysis [91,93,94].  
Genomic targeted therapy, recently approved for patients with castration-resistant PCa, includes the use of olaparib and rucaparib as blockers for PARP proteins. These chemotherapeutic agents inhibit poly(adenosine diphosphate-ribose) polymerase, a DNA repair factor [87,95,96]. Although there are few reports, olaparib could induce purpuric eruptions limited to the fingers, erythema nodosum, arthalgia, peripheral edema, skin rash, hypersensitivity, and alopecia [87,95]. The management of adverse dermatological events gives dermatology a fundamental role in the multidisciplinary team support for cancer patients.