Isotretinoin is effective in the treatment of severe acne and rosacea. Both parent drug and its main metabolite 4-oxo-isotretinoin are potentially teratogenic compounds and contain a carboxylic acid moiety.  

Efalizumab is a recombinant, humanized IgG1 monoclonal antibody used in the treatment of plaque psoriasis. Efalizumab specifically targets T cells, leading to the subsequent inhibition of T-cell activation. The recent cases (three confirmed and one unconfirmed but suspected case) of the demyelinating disease progressive multifocal leukoencephalopathy (PML) have resulted in efalizumab being pulled from the market by European and Canadian regulatory agencies .

Dermatitis herpetiformis is a rare disease that should be considered the cutaneous expression of a gluten-sensitive enteropathy indistinguishable from celiac disease. Dermatitis herpetiformis is often misdiagnosed and to date no guidelines for the management of dermatitis herpetiformis have been published in Literature. 

Psoriasis is an immune-mediated, chronic, inflammatory disease that significantly impairs both physical and emotional aspects of an individual's quality of life. Vitiligo leads to depigmentation of skin, in which some or all melanocytes in the interfollicular epidermis and occasionally those in the hair follicles are selectively destroyed. The coexistence of the two disorders is rarely seen. 

 Neopterin is an immunological marker of cellular immune activation. Etanercept is a tumor necrosis factor-alpha (TNF-alpha) antagonist that decreases excessive levels of TNF-alpha associated with inflammatory disease down to physiological levels.