Psoriasis inversa (inverse psoriasis)

Pso­ria­sis inver­sa is a spe­cial form of pso­ria­sis that main­ly occurs in skin folds and flex­or regi­ons. In con­trast to clas­sic pso­ria­sis vul­ga­ris, which is main­ly loca­li­zed on the exten­sor sides of the joints, the inver­se form pre­fers to affect the arm­pits, gro­in, the area under the breasts, the glu­te­al fold and the geni­tal and anal area. Around three to seven per­cent of all pso­ria­sis pati­ents suf­fer from this form. As with other forms of pso­ria­sis, the cau­se is a gene­tic pre­dis­po­si­ti­on in com­bi­na­ti­on with trig­ger fac­tors such as infec­tions, stress, cer­tain medi­ca­ti­ons or mecha­ni­cal irri­ta­ti­on. In the case of pso­ria­sis inver­sa, mois­tu­re, heat and fric­tion in the skin folds exa­cer­ba­te the sym­ptoms. The appearance dif­fers signi­fi­cant­ly from clas­sic pso­ria­sis: the skin shows shar­ply defi­ned, shi­ny, deep red to pur­ple plaques wit­hout the typi­cal sil­very sca­ling, as the mois­tu­re in the skin folds pre­vents the for­ma­ti­on of sca­les. The skin may ooze and is often mace­ra­ted. Dia­gno­sis can be dif­fi­cult as the appearance is aty­pi­cal and can easi­ly be con­fu­sed with fun­gal infec­tions, inter­t­ri­go or other skin con­di­ti­ons. A skin bio­psy can con­firm the dia­gno­sis. Tre­at­ment is chal­len­ging as the affec­ted are­as are sen­si­ti­ve and sweat pro­fu­se­ly. Topi­cal cor­ti­cos­te­ro­ids must be dosed careful­ly as the skin in skin folds absorbs acti­ve ingre­di­ents more rea­di­ly. Cal­ci­neu­rin inhi­bi­tors such as tacro­li­mus or pime­cro­li­mus are well tole­ra­ted. It is important to keep the skin folds dry, wear airy clot­hing and redu­ce excess weight. In seve­re cases, sys­te­mic the­ra­pies such as bio­lo­gics may be neces­sa­ry. As with other forms of pso­ria­sis, the pro­gno­sis is chro­nic, but can be well con­trol­led with good therapy.