TIlE NATURE OF DANDRUFF 127 i:7:f: ....... ' • ' .•- ' .... '"• ..... 5.. •v ...,.• •--:,• •.• • . ..•'•.•- • ':' :'" '•" *"'..' ..... ' •- •':5•.' '"? ...... •.:....Z•',•?f '"' . ....... • •. :. ........................................................... .. ....... ..,.- • ..... -v. •:"".' ' ..... • - :::':::" :, ß •.. ß ... :•.• '•:•.• ....... :...,..•'• •'.'... /%:-... :.•...• •: . '•. ' - :...: * ß . •- •. .:: s.:, ½.½•:. •' . .: . •.•. .*"• •i•.... ..•.., •,.: '" ....... . .................... ..., ...... '4 .... ,•' zs •. .•':½".•'•.• ':•..•- .•..,.. • . •' .: •7• •':..• ..... " '• '• '"'½ d '- '-'. . %' •'•'•..•. •.:*•:• •: ..• '.•:. •-• ½•:.,. a •:'•. ::,.. • 'v::'.. .:,• t.. .•" '•.' .• • .•& '. :. ..:•:: . . •-- •.: ..... -. ,•.: •,....•. •... • •. **• ..... ,.,..• ....... .,-* ..•. • .... ß ,,.. •...• .... • ..... ':,'.• ""• '•'.': ,:' ......... •, ß .:V C". ...... .: ...... .. •." .':{•. ::-'., '.' - •.:...• ß .. . ...... .... .... ,,.. . ß . ..• .... ½.½ • •.'.: •..%.. ,•... . . % . ,•.. :• ....... . • ........... '. • .......... •:• . .......... :•., - •...•?. .. t '•,...-. .,.:•. .•. ?:.'.' .,.. '-':-. ....... •...., . . . •: ...., 51½' 4.. •?., •...... •:.: . • ..... 4 •....• "':,5.• -•' .,• i-.• ./:•., ':' .: .....¾ , •, .:•...:•..•.• -.• -T:- ..%.- '•'• •..(½" •'.'•:• .,"-...: '• .•c.'... . • ...:: .'.--, :. ,.• .it.....-,e. ',•:. :....•., .:........:. 3½ '7::' -a •.•. ,....5½ -' .: • .. ' h .... '. : .... ::: .... • .. •..•..."• ½: .... "'•2-,.,-,... :.•.:¾-• ....::::•.•.:: .... ......:'"•..-::...',.....:.'.'•, •.• •"•.:. •.• ,.. .. . :%.....• - .•... "::.':• •.•.•.•:. .• .... ..& .... ..•.:,,:.., .,.... ::•..,.•.-.•,•.•..•.,.2•. .•...•.•.::•,..•:•............• ..... .: •(:. :%.' ....... :, . ... •.. '.- '"'• •:•-, :• ....... f,.....3:'::• •'"':" ,•, •:'* :' 7-.. "": "*' •• -- =:, ..:%.:• .... .'-• :.,.. ..... .:: .' ' .• * .. ....... .. "t-? ,• • • '•' .... • .-- -'• Figure 5. Normal scalp of young adult (H&E, •65 x). Papillae projet[ deeply into the epiSermis. Bete riSges are long. Capillaries within papillae drain in[o subepiSermal plexus of •enubs (partly shown on papilla on right). •ekness of epidermis and waviness of [he 8ermo-epidermal line vary greatly •om spec•en to specimen Table III Influence of Age on the Corneocyte Count Nondandruff Dandruff Subjects Corneocytes (/cm -•) Subjects Corneocytes (/cm -ø) Number 81 CM • 520 800 Nnmber 91 CM 873 000 Mean age 28 SD 0.22 Mean age 29 SD 0.22 (Range 21 to 46) (Range 21 to 48) Nnmber 45 CM 367 100 Number 21 C,M 636 800 Mean age 63 SD 0.20 Mean age 62 SD 0.17 (Range 51 to 79) (Range 53 to 72) '*Geometric Mean. and dermis. This was a faulty observation, which we now hasten to rectify. By studying serial sections of dandruff specimens, one can discern the sequence of events. The parakeratotic scale is the second stage of a transient episode of

128 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Figure 6. Spongiotic microvesicle (H&E, 260 x). Capillary has "squirted" serum and inflammatory cells into epidermis. Swollen and separated epidermal cells are beginning to degenerate. Infiltrate of mononuclear cells surrounds venule below focal inflammation. The first change takes place in the papilla, usually involv- ing two or three adjacent ones. The capillary dilates and a mixture of neutro- philes and mononuclear emigrate into the papillary space (Fig. 6). The venule draining this small focus of inflammation shows an increased perivas- cular infiltrate of round cells. The inflammatory cells leaving the capillary mi- grate into the epidermis, inducing intercellular edema. The spaces between the cells become wider, an appearance termed spongiosis. Sometimes the cells become completely detached and undergo necrosis forming a small micro- vesicle (Fig. 6). The granular layer quickly disappears in the affected zone and is replaced by parakeratotic cells. Initially these are infiltrated with poly- morphonuclear leukocytes (Fig. 7). Soon after, the inflammation abates and inflammatory cells no longer wander into the epidermis. The epidermis re- covers and starts to form a normal horny layer. At this stage, the parakeratotic segment forms a thin cap over the regenerating horny layer before disappear- pearing altogether (Fig. 8). This "pulse" or burst of inflammatory activity is nor peculiar to dandruff. It was beautifully described by Civatte in his classic studies of psoriasis (11).