Lichenoid interface dermatitis Key Features Basal layer is destroyed Civatte bodies Sawtooth rete pattern Causes of lichenoid interface dermatitis Lichen planus Benign lichenoid keratosis (BLK, lichen planus–like keratosis) Lichenoid drug eruption Lichenoid graft-versus-host disease (GvHD) Hypertrophic lupus erythematosus Lichenoid regression…
Solar lentigo Key Features Thin rete with bulbous tips “dipped in chocolate” Differential Diagnosis Reticulated seborrheic keratosis looks similar to a lentigo but with anastomosis of rete and horn cysts. Melanotic macule Key Features Common on the lips and genitalia…
Blue sweat gland tumors differentiate toward the secretory portion of the sweat gland. Red sweat gland tumors differentiate toward the sweat duct. Sweat duct tumors often demonstrate clear cell change. Most sweat gland tumors can show at least focal decapitation…
Pilar neoplasms Pilar neoplasms differentiate toward (resemble) various parts of the normal hair follicle. They are named according to what they resemble. Before reading this chapter, review the discussion of hair anatomy in Chapter 1 . Blue pilar tumors differentiate…
Actinic keratosis Key Features Crowding, disorder, and atypia of epidermal keratinocytes Arises from the basal layer Solar elastosis typically present Atypical cells commonly surround the follicular infundibulum. In two-dimensional sections, they appear to form a shoulder zone peripheral to the…
Benign acanthomas Acanthomas are benign cutaneous neoplasms characterized by an expansion of the epidermis. The acanthoma may be composed of clones of cells that displace or compress the preexisting epidermis. In contrast to the reactive acanthosis seen in inflammatory disorders,…
Insects Insect Bites and Stings (Class Insecta) Key features ▪ Pruritic papules sometimes progress to vesiculobullae or persistent prurigo nodularis-like lesions ▪ Papular urticaria may be localized to sites of bites or generalized ▪ Pseudolymphomatous reactions occasionally occur ▪ Anaphylaxis…
Plant Dermatitis Joao Paulo Niemeyer-Corbellini Omar Lupi Laila Klotz Livia Montelo Synonym Plant dermatitis Key Points Plant dermatitis may be produced by different plant species. It is increasing in incidence worldwide. It may be classified as mechanical injury, primary irritant (toxic) dermatitis, allergic phytodermatitis,…
Key Points Blood-sucking parasites specialized to certain types of human hair. Body but not hair lice transmit typhus and trench fever. Highest prevalence is in Caucasians owing to their more cylindrical hair structure. Nits are cemented to hair shafts predominantly…
Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports Open full size image Methicillin-resistant Staphylococcus aureus (MRSA) bacteria have developed resistance to β-lactam…