Pharmaceutical care when dispensing OTC medications for the symptomatic treatment of skin lesions

Dermatitis Dermatitis is a general term denoting an inflammatory response of the skin to injuries from irritants, allergens, or trauma. Eczema is often used as a synonym for dermatitis.

Seborrheic dermatitis

Dermatologic Infections

Folliculitis

Fungal infections

13 Dermatophytosis and Superficial Mycoses Microsporum Trichophyton Epidermophyton Malassezia furfur P. werneckii Piedraia hortae Trichosporon beigelii Dermatophytes Superficial Mycoses

Mycoses of Skin, Hair, and Nails Mycoses of skin, hair, and nails are grouped according to which layers are affected and clinical manifestations Superficial mycoses are fungal infections of the outermost keratinized layers of the skin or hair shaft resulting in essentially no pathological changes. No cellular immune response in elicited & minimal humoral host response - IgA These mycoses are largely cosmetic involving skin pigmentation or forming nodules along distal hair shafts – often asymptomatic & host is unaware

Mycoses of Skin, Hair, and Nails The superficial mycoses are: Malassezia furfur  tinea versicolor (seborrhea?, dandruff?) Phaeoannelomyces werneckii  tinea nigra Piedraia hortae  black piedra Trichosporon beigelii  white piedra *Dermatophytosis involve deeper layers of skin, hair, and nails with varied clinical manifestations and are caused by species of the fungal genera Trichophyton, Epidermophyton, and Microsporum (in order of commonality).

Dermatophytes Dermatophytes are keratinophilic fungi – they possess keratinase allowing them to utilize keratin as a nutrient & energy source They infect the keratinized (horny) outer layer of the scalp, glabrous skin, and nails causing tinea or ringworm Although no living tissue is invaded (keratinized stratum only colonized) the infection induces an allergic and inflammatory eczematous response in the host Lesions on skin and sometimes nails have a characteristic circular pattern that was mistaken by ancient physicians as being a worm down in the tissue These lesions are still today called ringworm infections even though the etiology is known to be a fungus rather than a worm

Classical “Ringworm” Lesion

Dermatophytes Taxonomic classification –They belong to the phylum Deuteromycota (Fungi Imperfecti) –They are hyaline moulds (transparent / white) –Three genera comprise this group Microspourm Trichophyton Epidermophyton

Dermatophytes Classification –There are many species of dermatophytes but only a few are commonly encountered in developed countries –Identifying the dermatophytes to the species level is not usually required because antimicrobial therapy is the same for all isolates

Dermatophytes Direct Examination Treating skin and nail scrapings and “snippets” of hair with potassium hydroxide (KOH dissolves keratin but not chitin - hyphae) is usually very effective in detecting dermatophyte hyphae in clinical specimens. The addition of calcofluor white (1,4 polymer specific fluorochrome dye) and dimethylsulfoxide (DMSO) to the KOH and viewing with a fluorescent microscope is recommended. DMSO is a non-polar surfactant (wetting agent) which aids in clearing of the keratin by making KOH more soluble in the sample.

Dermatophytes Direct Examination –The pattern of growth in the infected hair taken directly from the patient is characteristic of some dermatophytic fungi Some grow only inside the hair shaft (endothrix) Some grow inside and outside the hair shaft (ectothrix)

CLINICAL MANIFESTATIONS Tinea means "ringworm" or "moth-like". Dermatologists use the term to refer to a variety of lesions of the skin or scalp. Tinea corporis - small lesions occurring anywhere on the body (figure 6, 7 and 8). Tinea pedis - "athlete's foot". Infection of toe webs and soles of feet. Tinea unguium (onychomycosis) - nails. Clipped and used for culture (figure 1). Tinea capitis - head. Frequently found in children (figure 3 and 4). Tinea cruris - "jock itch". Infection of the groin, perineum or perianal area. Tinea barbae - ringworm of the bearded areas of the face and neck (figure 5).

Figure 1 Onychomycosis due to Trychophyton rubrum, right and left great toe. Tinea unguium.

Tinea versicolor Characterized by a blotchy discoloration of skin which may itch. Up to 25% of the general population may have this lesion at any one time. Diagnosis is usually possible by direct microscopic examination of KOH-treated skin scrapings which show a typical aspect of mycelia and spores described as "spaghetti and meatballs." Tinea versicolor is caused by Malassezia furfur

Figure 3. A child with a ringworm (tinea) fungal infection on the left side of his face and left ear. “Tinea faciei” or "Tinea capitis" is the name used for infections of the face caused by a dermatophytic fungus, but not including infection of the bearded areas, which are called “tinea barbae”. Tinea faciei infections are uncommon, and are often initially misdiagnosed

Figure 4. A child with ringworm of the scalp, called “tinea capitis”, caused by a Microsporum sp.. Tinea capitis is an infection of the scalp caused by mold-like fungi called dermatophytes, which thrive in warm, moist areas. Susceptibility to tinea infection is increased by poor hygiene, prolonged moist skin, and minor skin or scalp injuries.

Figure 5. Ringworm of the bearded areas of the face and neck, known as “tinea barbae”, or “barber’s itch”. Tinea barbae is due to a dermatophytic infection around the bearded area of men. Generally, the infection occurs as a follicular inflammation, or as a cutaneous granulomatous lesion, i.e. a chronic inflammatory reaction

Figure 6. Tinea corporis lesions, or “ringworm” on this patient’s arm due to the dermatophytic fungus Trichophyton rubrum. Dermatophytic members of the genus Trichophyton inhabit the soil, humans or animals, and are some of the leading causes of hair, skin and nail infections, or dermatophytosis in their human hosts.

Figure 7. Patient with ringworm on the arm, or tinea corporis due to Trichophyton mentagrophytes. The genus Trichophyton inhabits the soil, humans or animals, and is one of the leading causes of hair, skin and nail infections, or dermatophytosis in humans

This patient, a native of New Guinea, has ringworm on the skin of the right axilla and flank due to Trichophyton rubrum. Usually occurring as a skin parasite, or dermatophyte on man and animals, the genus Trichophyton is characterized by colorless spores that can cause ringworm on the body. This condition is called Tinea corporis.