Resolving Quandaries in Dermatology, Pathology & Dermatopathology

Telogen Effluvium—An Inflammatory Disease?

“Telogen effluvium signifies the loss of normal club hairs from resting follicles which have performed the ritual of involution, catagen, in the prescribed [sic] fashion. Inflammatory signs or other histologic abnormalities are necessarily m…

Histologic Diagnosis of Inflammatory Skin Diseases

Identification of Basic Patterns: Skin: Pustular Dermatitis

See Fig. 5.307 A&B. Figure 5.307 Pustular dermatitis. A. Infundibular. B. Surface epidermal. Although most pustules in skin are housed in infundibular epidermis (Fig. 5.308 A&B), many are lodged in surface epidermis (Fig. 5.309 A&B)….

Histologic Diagnosis of Inflammatory Skin Diseases

Arthropod assaults

Arthropod assaults Synonyms Insect “bite” Bug bite Insect bite reaction Papular urticaria Lichen urticatus Strophulus Presentation stereotypical Age and sex Any age and both sexes Distribution of lesions At times only a single lesion a…

Histologic Diagnosis of Inflammatory Skin Diseases

Confusing Terms (to be Avoided Scrupulously)

APOPTOSIS [Gk. apo- (away from) + ptosis (a falling)]: Reputed to be a specific type of cell death in which dead cells are said to undergo fragmentation by implosion with subsequent phagocytosis of nuclear debris (Fig. 3.40). The process is claimed…

Histologic Diagnosis of Inflammatory Skin Diseases


Images 10.105.1A: Perivascular dermatitis, lymphocytic + 10.105.1B: Short hyphae and spores in a cornified layer whose pattern is basket-weave = Tinea versicolor ¬†Unlike the situation in dermatophytosis, in which the cornified layer usual…

Histologic Diagnosis of Inflammatory Skin Diseases

Tinea versicolor

Tinea versicolor Synonyms Pityriasis versicolor Dermatomycosis furfuracea Presentation stereotypical Age and sex Young adult men especially, but anyone can be affected Distribution of lesions Trunk particularly, but also the proximal aspect of the e…

Histologic Diagnosis of Inflammatory Skin Diseases

Herpes gestationis

Herpes gestationis Synonyms Pemphigoid gestationis Dermatitis multiformis gestationis Gestational pemphigoid Presentation stereotypical Age and sex Women in the second trimester of pregnancy, but may develop at any stage of gestation Distribution…

Differential Diagnosis in Dermatopathology


The erythroderma of psoriasis and the erythroderma of mycosis fungoides have several attributes histopathologic in common: psoriasiform acanthosis, an infiltrate in the dermis that consists mostly of lymphocytes and is situated especially around and…

Differential Diagnosis in Dermatopathology

Psoriasis on volar skin vs. Dyshidrotic dermatitis

An inflammatory process caused by superficial fungi, i.e., fungi situated superficially in the cornified layer and in other cornified structures, and expressed clinically as smooth-surfaced papules, scaly papules, scaly plaques, nodules, pustules, v…