Abstract
Given that the skin is a major target organ of numerous hormones for which it expresses functional receptors, it is not surprising that excessive or insufficient systemic levels of these hormones induce clinically relevant cutaneous responses. These can manifest as general skin symptoms and signs such as pruritus, skin dryness, seborrhoea, hair loss, hypertrichosis, hirsutism, hyperhidrosis and/or hyperpigmentation, any of which prompts consideration of an underlying endocrine disease. In addition, characteristic skin lesions such as palmar erythema, gingival hyperpigmentation, stretch marks (striae distensae), acanthosis nigricans, pretibial myxoedema, necrobiosis lipoidica, melasma and acneform eruptions provide invaluable diagnostic clues to the possibility of unrecognized endocrine disease. More recently, the field has been revolutionized by the recognition that human skin is also a major endocrine and neuroendocrine organ which produces and/or metabolizes not only all classes of steroid hormones but also multiple peptide (neuro‐) hormones, neuropeptides and neurotransmitters. These impact profoundly on skin physiology and pathology at multiple levels, ranging from skin barrier function and neurogenic skin inflammation via wound healing to cutaneous stress responses. This has important implications for future dermatological therapy.